InstructionSimplify.cpp revision 223017
1199481Srdivacky//===- InstructionSimplify.cpp - Fold instruction operands ----------------===// 2199481Srdivacky// 3199481Srdivacky// The LLVM Compiler Infrastructure 4199481Srdivacky// 5199481Srdivacky// This file is distributed under the University of Illinois Open Source 6199481Srdivacky// License. See LICENSE.TXT for details. 7199481Srdivacky// 8199481Srdivacky//===----------------------------------------------------------------------===// 9199481Srdivacky// 10199481Srdivacky// This file implements routines for folding instructions into simpler forms 11218893Sdim// that do not require creating new instructions. This does constant folding 12218893Sdim// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either 13218893Sdim// returning a constant ("and i32 %x, 0" -> "0") or an already existing value 14218893Sdim// ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been 15218893Sdim// simplified: This is usually true and assuming it simplifies the logic (if 16218893Sdim// they have not been simplified then results are correct but maybe suboptimal). 17199481Srdivacky// 18199481Srdivacky//===----------------------------------------------------------------------===// 19199481Srdivacky 20218893Sdim#define DEBUG_TYPE "instsimplify" 21221345Sdim#include "llvm/Operator.h" 22218893Sdim#include "llvm/ADT/Statistic.h" 23199481Srdivacky#include "llvm/Analysis/InstructionSimplify.h" 24199481Srdivacky#include "llvm/Analysis/ConstantFolding.h" 25218893Sdim#include "llvm/Analysis/Dominators.h" 26218893Sdim#include "llvm/Analysis/ValueTracking.h" 27221345Sdim#include "llvm/Support/ConstantRange.h" 28218893Sdim#include "llvm/Support/PatternMatch.h" 29199481Srdivacky#include "llvm/Support/ValueHandle.h" 30218893Sdim#include "llvm/Target/TargetData.h" 31199481Srdivackyusing namespace llvm; 32199481Srdivackyusing namespace llvm::PatternMatch; 33199481Srdivacky 34218893Sdimenum { RecursionLimit = 3 }; 35218893Sdim 36218893SdimSTATISTIC(NumExpand, "Number of expansions"); 37218893SdimSTATISTIC(NumFactor , "Number of factorizations"); 38218893SdimSTATISTIC(NumReassoc, "Number of reassociations"); 39218893Sdim 40218893Sdimstatic Value *SimplifyAndInst(Value *, Value *, const TargetData *, 41218893Sdim const DominatorTree *, unsigned); 42218893Sdimstatic Value *SimplifyBinOp(unsigned, Value *, Value *, const TargetData *, 43218893Sdim const DominatorTree *, unsigned); 44218893Sdimstatic Value *SimplifyCmpInst(unsigned, Value *, Value *, const TargetData *, 45218893Sdim const DominatorTree *, unsigned); 46218893Sdimstatic Value *SimplifyOrInst(Value *, Value *, const TargetData *, 47218893Sdim const DominatorTree *, unsigned); 48218893Sdimstatic Value *SimplifyXorInst(Value *, Value *, const TargetData *, 49218893Sdim const DominatorTree *, unsigned); 50218893Sdim 51218893Sdim/// ValueDominatesPHI - Does the given value dominate the specified phi node? 52218893Sdimstatic bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) { 53218893Sdim Instruction *I = dyn_cast<Instruction>(V); 54218893Sdim if (!I) 55218893Sdim // Arguments and constants dominate all instructions. 56218893Sdim return true; 57218893Sdim 58218893Sdim // If we have a DominatorTree then do a precise test. 59218893Sdim if (DT) 60218893Sdim return DT->dominates(I, P); 61218893Sdim 62218893Sdim // Otherwise, if the instruction is in the entry block, and is not an invoke, 63218893Sdim // then it obviously dominates all phi nodes. 64218893Sdim if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() && 65218893Sdim !isa<InvokeInst>(I)) 66218893Sdim return true; 67218893Sdim 68218893Sdim return false; 69218893Sdim} 70218893Sdim 71218893Sdim/// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning 72218893Sdim/// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is 73218893Sdim/// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS. 74218893Sdim/// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)". 75218893Sdim/// Returns the simplified value, or null if no simplification was performed. 76218893Sdimstatic Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS, 77218893Sdim unsigned OpcToExpand, const TargetData *TD, 78218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 79218893Sdim Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand; 80218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 81218893Sdim if (!MaxRecurse--) 82218893Sdim return 0; 83218893Sdim 84218893Sdim // Check whether the expression has the form "(A op' B) op C". 85218893Sdim if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS)) 86218893Sdim if (Op0->getOpcode() == OpcodeToExpand) { 87218893Sdim // It does! Try turning it into "(A op C) op' (B op C)". 88218893Sdim Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS; 89218893Sdim // Do "A op C" and "B op C" both simplify? 90218893Sdim if (Value *L = SimplifyBinOp(Opcode, A, C, TD, DT, MaxRecurse)) 91218893Sdim if (Value *R = SimplifyBinOp(Opcode, B, C, TD, DT, MaxRecurse)) { 92218893Sdim // They do! Return "L op' R" if it simplifies or is already available. 93218893Sdim // If "L op' R" equals "A op' B" then "L op' R" is just the LHS. 94218893Sdim if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand) 95218893Sdim && L == B && R == A)) { 96218893Sdim ++NumExpand; 97218893Sdim return LHS; 98218893Sdim } 99218893Sdim // Otherwise return "L op' R" if it simplifies. 100218893Sdim if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, TD, DT, 101218893Sdim MaxRecurse)) { 102218893Sdim ++NumExpand; 103218893Sdim return V; 104218893Sdim } 105218893Sdim } 106218893Sdim } 107218893Sdim 108218893Sdim // Check whether the expression has the form "A op (B op' C)". 109218893Sdim if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS)) 110218893Sdim if (Op1->getOpcode() == OpcodeToExpand) { 111218893Sdim // It does! Try turning it into "(A op B) op' (A op C)". 112218893Sdim Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1); 113218893Sdim // Do "A op B" and "A op C" both simplify? 114218893Sdim if (Value *L = SimplifyBinOp(Opcode, A, B, TD, DT, MaxRecurse)) 115218893Sdim if (Value *R = SimplifyBinOp(Opcode, A, C, TD, DT, MaxRecurse)) { 116218893Sdim // They do! Return "L op' R" if it simplifies or is already available. 117218893Sdim // If "L op' R" equals "B op' C" then "L op' R" is just the RHS. 118218893Sdim if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand) 119218893Sdim && L == C && R == B)) { 120218893Sdim ++NumExpand; 121218893Sdim return RHS; 122218893Sdim } 123218893Sdim // Otherwise return "L op' R" if it simplifies. 124218893Sdim if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, TD, DT, 125218893Sdim MaxRecurse)) { 126218893Sdim ++NumExpand; 127218893Sdim return V; 128218893Sdim } 129218893Sdim } 130218893Sdim } 131218893Sdim 132218893Sdim return 0; 133218893Sdim} 134218893Sdim 135218893Sdim/// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term 136218893Sdim/// using the operation OpCodeToExtract. For example, when Opcode is Add and 137218893Sdim/// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)". 138218893Sdim/// Returns the simplified value, or null if no simplification was performed. 139218893Sdimstatic Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS, 140218893Sdim unsigned OpcToExtract, const TargetData *TD, 141218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 142218893Sdim Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract; 143218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 144218893Sdim if (!MaxRecurse--) 145218893Sdim return 0; 146218893Sdim 147218893Sdim BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS); 148218893Sdim BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS); 149218893Sdim 150218893Sdim if (!Op0 || Op0->getOpcode() != OpcodeToExtract || 151218893Sdim !Op1 || Op1->getOpcode() != OpcodeToExtract) 152218893Sdim return 0; 153218893Sdim 154218893Sdim // The expression has the form "(A op' B) op (C op' D)". 155218893Sdim Value *A = Op0->getOperand(0), *B = Op0->getOperand(1); 156218893Sdim Value *C = Op1->getOperand(0), *D = Op1->getOperand(1); 157218893Sdim 158218893Sdim // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)". 159218893Sdim // Does the instruction have the form "(A op' B) op (A op' D)" or, in the 160218893Sdim // commutative case, "(A op' B) op (C op' A)"? 161218893Sdim if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) { 162218893Sdim Value *DD = A == C ? D : C; 163218893Sdim // Form "A op' (B op DD)" if it simplifies completely. 164218893Sdim // Does "B op DD" simplify? 165218893Sdim if (Value *V = SimplifyBinOp(Opcode, B, DD, TD, DT, MaxRecurse)) { 166218893Sdim // It does! Return "A op' V" if it simplifies or is already available. 167218893Sdim // If V equals B then "A op' V" is just the LHS. If V equals DD then 168218893Sdim // "A op' V" is just the RHS. 169218893Sdim if (V == B || V == DD) { 170218893Sdim ++NumFactor; 171218893Sdim return V == B ? LHS : RHS; 172218893Sdim } 173218893Sdim // Otherwise return "A op' V" if it simplifies. 174218893Sdim if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, TD, DT, MaxRecurse)) { 175218893Sdim ++NumFactor; 176218893Sdim return W; 177218893Sdim } 178218893Sdim } 179218893Sdim } 180218893Sdim 181218893Sdim // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)". 182218893Sdim // Does the instruction have the form "(A op' B) op (C op' B)" or, in the 183218893Sdim // commutative case, "(A op' B) op (B op' D)"? 184218893Sdim if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) { 185218893Sdim Value *CC = B == D ? C : D; 186218893Sdim // Form "(A op CC) op' B" if it simplifies completely.. 187218893Sdim // Does "A op CC" simplify? 188218893Sdim if (Value *V = SimplifyBinOp(Opcode, A, CC, TD, DT, MaxRecurse)) { 189218893Sdim // It does! Return "V op' B" if it simplifies or is already available. 190218893Sdim // If V equals A then "V op' B" is just the LHS. If V equals CC then 191218893Sdim // "V op' B" is just the RHS. 192218893Sdim if (V == A || V == CC) { 193218893Sdim ++NumFactor; 194218893Sdim return V == A ? LHS : RHS; 195218893Sdim } 196218893Sdim // Otherwise return "V op' B" if it simplifies. 197218893Sdim if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, TD, DT, MaxRecurse)) { 198218893Sdim ++NumFactor; 199218893Sdim return W; 200218893Sdim } 201218893Sdim } 202218893Sdim } 203218893Sdim 204218893Sdim return 0; 205218893Sdim} 206218893Sdim 207218893Sdim/// SimplifyAssociativeBinOp - Generic simplifications for associative binary 208218893Sdim/// operations. Returns the simpler value, or null if none was found. 209218893Sdimstatic Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS, 210218893Sdim const TargetData *TD, 211218893Sdim const DominatorTree *DT, 212218893Sdim unsigned MaxRecurse) { 213218893Sdim Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc; 214218893Sdim assert(Instruction::isAssociative(Opcode) && "Not an associative operation!"); 215218893Sdim 216218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 217218893Sdim if (!MaxRecurse--) 218218893Sdim return 0; 219218893Sdim 220218893Sdim BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS); 221218893Sdim BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS); 222218893Sdim 223218893Sdim // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely. 224218893Sdim if (Op0 && Op0->getOpcode() == Opcode) { 225218893Sdim Value *A = Op0->getOperand(0); 226218893Sdim Value *B = Op0->getOperand(1); 227218893Sdim Value *C = RHS; 228218893Sdim 229218893Sdim // Does "B op C" simplify? 230218893Sdim if (Value *V = SimplifyBinOp(Opcode, B, C, TD, DT, MaxRecurse)) { 231218893Sdim // It does! Return "A op V" if it simplifies or is already available. 232218893Sdim // If V equals B then "A op V" is just the LHS. 233218893Sdim if (V == B) return LHS; 234218893Sdim // Otherwise return "A op V" if it simplifies. 235218893Sdim if (Value *W = SimplifyBinOp(Opcode, A, V, TD, DT, MaxRecurse)) { 236218893Sdim ++NumReassoc; 237218893Sdim return W; 238218893Sdim } 239218893Sdim } 240218893Sdim } 241218893Sdim 242218893Sdim // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely. 243218893Sdim if (Op1 && Op1->getOpcode() == Opcode) { 244218893Sdim Value *A = LHS; 245218893Sdim Value *B = Op1->getOperand(0); 246218893Sdim Value *C = Op1->getOperand(1); 247218893Sdim 248218893Sdim // Does "A op B" simplify? 249218893Sdim if (Value *V = SimplifyBinOp(Opcode, A, B, TD, DT, MaxRecurse)) { 250218893Sdim // It does! Return "V op C" if it simplifies or is already available. 251218893Sdim // If V equals B then "V op C" is just the RHS. 252218893Sdim if (V == B) return RHS; 253218893Sdim // Otherwise return "V op C" if it simplifies. 254218893Sdim if (Value *W = SimplifyBinOp(Opcode, V, C, TD, DT, MaxRecurse)) { 255218893Sdim ++NumReassoc; 256218893Sdim return W; 257218893Sdim } 258218893Sdim } 259218893Sdim } 260218893Sdim 261218893Sdim // The remaining transforms require commutativity as well as associativity. 262218893Sdim if (!Instruction::isCommutative(Opcode)) 263218893Sdim return 0; 264218893Sdim 265218893Sdim // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely. 266218893Sdim if (Op0 && Op0->getOpcode() == Opcode) { 267218893Sdim Value *A = Op0->getOperand(0); 268218893Sdim Value *B = Op0->getOperand(1); 269218893Sdim Value *C = RHS; 270218893Sdim 271218893Sdim // Does "C op A" simplify? 272218893Sdim if (Value *V = SimplifyBinOp(Opcode, C, A, TD, DT, MaxRecurse)) { 273218893Sdim // It does! Return "V op B" if it simplifies or is already available. 274218893Sdim // If V equals A then "V op B" is just the LHS. 275218893Sdim if (V == A) return LHS; 276218893Sdim // Otherwise return "V op B" if it simplifies. 277218893Sdim if (Value *W = SimplifyBinOp(Opcode, V, B, TD, DT, MaxRecurse)) { 278218893Sdim ++NumReassoc; 279218893Sdim return W; 280218893Sdim } 281218893Sdim } 282218893Sdim } 283218893Sdim 284218893Sdim // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely. 285218893Sdim if (Op1 && Op1->getOpcode() == Opcode) { 286218893Sdim Value *A = LHS; 287218893Sdim Value *B = Op1->getOperand(0); 288218893Sdim Value *C = Op1->getOperand(1); 289218893Sdim 290218893Sdim // Does "C op A" simplify? 291218893Sdim if (Value *V = SimplifyBinOp(Opcode, C, A, TD, DT, MaxRecurse)) { 292218893Sdim // It does! Return "B op V" if it simplifies or is already available. 293218893Sdim // If V equals C then "B op V" is just the RHS. 294218893Sdim if (V == C) return RHS; 295218893Sdim // Otherwise return "B op V" if it simplifies. 296218893Sdim if (Value *W = SimplifyBinOp(Opcode, B, V, TD, DT, MaxRecurse)) { 297218893Sdim ++NumReassoc; 298218893Sdim return W; 299218893Sdim } 300218893Sdim } 301218893Sdim } 302218893Sdim 303218893Sdim return 0; 304218893Sdim} 305218893Sdim 306218893Sdim/// ThreadBinOpOverSelect - In the case of a binary operation with a select 307218893Sdim/// instruction as an operand, try to simplify the binop by seeing whether 308218893Sdim/// evaluating it on both branches of the select results in the same value. 309218893Sdim/// Returns the common value if so, otherwise returns null. 310218893Sdimstatic Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS, 311218893Sdim const TargetData *TD, 312218893Sdim const DominatorTree *DT, 313218893Sdim unsigned MaxRecurse) { 314218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 315218893Sdim if (!MaxRecurse--) 316218893Sdim return 0; 317218893Sdim 318218893Sdim SelectInst *SI; 319218893Sdim if (isa<SelectInst>(LHS)) { 320218893Sdim SI = cast<SelectInst>(LHS); 321218893Sdim } else { 322218893Sdim assert(isa<SelectInst>(RHS) && "No select instruction operand!"); 323218893Sdim SI = cast<SelectInst>(RHS); 324218893Sdim } 325218893Sdim 326218893Sdim // Evaluate the BinOp on the true and false branches of the select. 327218893Sdim Value *TV; 328218893Sdim Value *FV; 329218893Sdim if (SI == LHS) { 330218893Sdim TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, TD, DT, MaxRecurse); 331218893Sdim FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, TD, DT, MaxRecurse); 332218893Sdim } else { 333218893Sdim TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), TD, DT, MaxRecurse); 334218893Sdim FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), TD, DT, MaxRecurse); 335218893Sdim } 336218893Sdim 337218893Sdim // If they simplified to the same value, then return the common value. 338218893Sdim // If they both failed to simplify then return null. 339218893Sdim if (TV == FV) 340218893Sdim return TV; 341218893Sdim 342218893Sdim // If one branch simplified to undef, return the other one. 343218893Sdim if (TV && isa<UndefValue>(TV)) 344218893Sdim return FV; 345218893Sdim if (FV && isa<UndefValue>(FV)) 346218893Sdim return TV; 347218893Sdim 348218893Sdim // If applying the operation did not change the true and false select values, 349218893Sdim // then the result of the binop is the select itself. 350218893Sdim if (TV == SI->getTrueValue() && FV == SI->getFalseValue()) 351218893Sdim return SI; 352218893Sdim 353218893Sdim // If one branch simplified and the other did not, and the simplified 354218893Sdim // value is equal to the unsimplified one, return the simplified value. 355218893Sdim // For example, select (cond, X, X & Z) & Z -> X & Z. 356218893Sdim if ((FV && !TV) || (TV && !FV)) { 357218893Sdim // Check that the simplified value has the form "X op Y" where "op" is the 358218893Sdim // same as the original operation. 359218893Sdim Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV); 360218893Sdim if (Simplified && Simplified->getOpcode() == Opcode) { 361218893Sdim // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS". 362218893Sdim // We already know that "op" is the same as for the simplified value. See 363218893Sdim // if the operands match too. If so, return the simplified value. 364218893Sdim Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue(); 365218893Sdim Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS; 366218893Sdim Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch; 367218893Sdim if (Simplified->getOperand(0) == UnsimplifiedLHS && 368218893Sdim Simplified->getOperand(1) == UnsimplifiedRHS) 369218893Sdim return Simplified; 370218893Sdim if (Simplified->isCommutative() && 371218893Sdim Simplified->getOperand(1) == UnsimplifiedLHS && 372218893Sdim Simplified->getOperand(0) == UnsimplifiedRHS) 373218893Sdim return Simplified; 374218893Sdim } 375218893Sdim } 376218893Sdim 377218893Sdim return 0; 378218893Sdim} 379218893Sdim 380218893Sdim/// ThreadCmpOverSelect - In the case of a comparison with a select instruction, 381218893Sdim/// try to simplify the comparison by seeing whether both branches of the select 382218893Sdim/// result in the same value. Returns the common value if so, otherwise returns 383218893Sdim/// null. 384218893Sdimstatic Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS, 385218893Sdim Value *RHS, const TargetData *TD, 386218893Sdim const DominatorTree *DT, 387218893Sdim unsigned MaxRecurse) { 388218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 389218893Sdim if (!MaxRecurse--) 390218893Sdim return 0; 391218893Sdim 392218893Sdim // Make sure the select is on the LHS. 393218893Sdim if (!isa<SelectInst>(LHS)) { 394218893Sdim std::swap(LHS, RHS); 395218893Sdim Pred = CmpInst::getSwappedPredicate(Pred); 396218893Sdim } 397218893Sdim assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!"); 398218893Sdim SelectInst *SI = cast<SelectInst>(LHS); 399218893Sdim 400218893Sdim // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it. 401218893Sdim // Does "cmp TV, RHS" simplify? 402218893Sdim if (Value *TCmp = SimplifyCmpInst(Pred, SI->getTrueValue(), RHS, TD, DT, 403218893Sdim MaxRecurse)) { 404218893Sdim // It does! Does "cmp FV, RHS" simplify? 405218893Sdim if (Value *FCmp = SimplifyCmpInst(Pred, SI->getFalseValue(), RHS, TD, DT, 406218893Sdim MaxRecurse)) { 407218893Sdim // It does! If they simplified to the same value, then use it as the 408218893Sdim // result of the original comparison. 409218893Sdim if (TCmp == FCmp) 410218893Sdim return TCmp; 411218893Sdim Value *Cond = SI->getCondition(); 412218893Sdim // If the false value simplified to false, then the result of the compare 413218893Sdim // is equal to "Cond && TCmp". This also catches the case when the false 414218893Sdim // value simplified to false and the true value to true, returning "Cond". 415218893Sdim if (match(FCmp, m_Zero())) 416218893Sdim if (Value *V = SimplifyAndInst(Cond, TCmp, TD, DT, MaxRecurse)) 417218893Sdim return V; 418218893Sdim // If the true value simplified to true, then the result of the compare 419218893Sdim // is equal to "Cond || FCmp". 420218893Sdim if (match(TCmp, m_One())) 421218893Sdim if (Value *V = SimplifyOrInst(Cond, FCmp, TD, DT, MaxRecurse)) 422218893Sdim return V; 423218893Sdim // Finally, if the false value simplified to true and the true value to 424218893Sdim // false, then the result of the compare is equal to "!Cond". 425218893Sdim if (match(FCmp, m_One()) && match(TCmp, m_Zero())) 426218893Sdim if (Value *V = 427218893Sdim SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()), 428218893Sdim TD, DT, MaxRecurse)) 429218893Sdim return V; 430218893Sdim } 431218893Sdim } 432218893Sdim 433218893Sdim return 0; 434218893Sdim} 435218893Sdim 436218893Sdim/// ThreadBinOpOverPHI - In the case of a binary operation with an operand that 437218893Sdim/// is a PHI instruction, try to simplify the binop by seeing whether evaluating 438218893Sdim/// it on the incoming phi values yields the same result for every value. If so 439218893Sdim/// returns the common value, otherwise returns null. 440218893Sdimstatic Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS, 441218893Sdim const TargetData *TD, const DominatorTree *DT, 442218893Sdim unsigned MaxRecurse) { 443218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 444218893Sdim if (!MaxRecurse--) 445218893Sdim return 0; 446218893Sdim 447218893Sdim PHINode *PI; 448218893Sdim if (isa<PHINode>(LHS)) { 449218893Sdim PI = cast<PHINode>(LHS); 450218893Sdim // Bail out if RHS and the phi may be mutually interdependent due to a loop. 451218893Sdim if (!ValueDominatesPHI(RHS, PI, DT)) 452218893Sdim return 0; 453218893Sdim } else { 454218893Sdim assert(isa<PHINode>(RHS) && "No PHI instruction operand!"); 455218893Sdim PI = cast<PHINode>(RHS); 456218893Sdim // Bail out if LHS and the phi may be mutually interdependent due to a loop. 457218893Sdim if (!ValueDominatesPHI(LHS, PI, DT)) 458218893Sdim return 0; 459218893Sdim } 460218893Sdim 461218893Sdim // Evaluate the BinOp on the incoming phi values. 462218893Sdim Value *CommonValue = 0; 463218893Sdim for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) { 464218893Sdim Value *Incoming = PI->getIncomingValue(i); 465218893Sdim // If the incoming value is the phi node itself, it can safely be skipped. 466218893Sdim if (Incoming == PI) continue; 467218893Sdim Value *V = PI == LHS ? 468218893Sdim SimplifyBinOp(Opcode, Incoming, RHS, TD, DT, MaxRecurse) : 469218893Sdim SimplifyBinOp(Opcode, LHS, Incoming, TD, DT, MaxRecurse); 470218893Sdim // If the operation failed to simplify, or simplified to a different value 471218893Sdim // to previously, then give up. 472218893Sdim if (!V || (CommonValue && V != CommonValue)) 473218893Sdim return 0; 474218893Sdim CommonValue = V; 475218893Sdim } 476218893Sdim 477218893Sdim return CommonValue; 478218893Sdim} 479218893Sdim 480218893Sdim/// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try 481218893Sdim/// try to simplify the comparison by seeing whether comparing with all of the 482218893Sdim/// incoming phi values yields the same result every time. If so returns the 483218893Sdim/// common result, otherwise returns null. 484218893Sdimstatic Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS, 485218893Sdim const TargetData *TD, const DominatorTree *DT, 486218893Sdim unsigned MaxRecurse) { 487218893Sdim // Recursion is always used, so bail out at once if we already hit the limit. 488218893Sdim if (!MaxRecurse--) 489218893Sdim return 0; 490218893Sdim 491218893Sdim // Make sure the phi is on the LHS. 492218893Sdim if (!isa<PHINode>(LHS)) { 493218893Sdim std::swap(LHS, RHS); 494218893Sdim Pred = CmpInst::getSwappedPredicate(Pred); 495218893Sdim } 496218893Sdim assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!"); 497218893Sdim PHINode *PI = cast<PHINode>(LHS); 498218893Sdim 499218893Sdim // Bail out if RHS and the phi may be mutually interdependent due to a loop. 500218893Sdim if (!ValueDominatesPHI(RHS, PI, DT)) 501218893Sdim return 0; 502218893Sdim 503218893Sdim // Evaluate the BinOp on the incoming phi values. 504218893Sdim Value *CommonValue = 0; 505218893Sdim for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) { 506218893Sdim Value *Incoming = PI->getIncomingValue(i); 507218893Sdim // If the incoming value is the phi node itself, it can safely be skipped. 508218893Sdim if (Incoming == PI) continue; 509218893Sdim Value *V = SimplifyCmpInst(Pred, Incoming, RHS, TD, DT, MaxRecurse); 510218893Sdim // If the operation failed to simplify, or simplified to a different value 511218893Sdim // to previously, then give up. 512218893Sdim if (!V || (CommonValue && V != CommonValue)) 513218893Sdim return 0; 514218893Sdim CommonValue = V; 515218893Sdim } 516218893Sdim 517218893Sdim return CommonValue; 518218893Sdim} 519218893Sdim 520199989Srdivacky/// SimplifyAddInst - Given operands for an Add, see if we can 521199481Srdivacky/// fold the result. If not, this returns null. 522218893Sdimstatic Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 523218893Sdim const TargetData *TD, const DominatorTree *DT, 524218893Sdim unsigned MaxRecurse) { 525199481Srdivacky if (Constant *CLHS = dyn_cast<Constant>(Op0)) { 526199481Srdivacky if (Constant *CRHS = dyn_cast<Constant>(Op1)) { 527199481Srdivacky Constant *Ops[] = { CLHS, CRHS }; 528199989Srdivacky return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), 529199989Srdivacky Ops, 2, TD); 530199989Srdivacky } 531218893Sdim 532199989Srdivacky // Canonicalize the constant to the RHS. 533199989Srdivacky std::swap(Op0, Op1); 534199989Srdivacky } 535218893Sdim 536218893Sdim // X + undef -> undef 537218893Sdim if (match(Op1, m_Undef())) 538218893Sdim return Op1; 539218893Sdim 540218893Sdim // X + 0 -> X 541218893Sdim if (match(Op1, m_Zero())) 542218893Sdim return Op0; 543218893Sdim 544218893Sdim // X + (Y - X) -> Y 545218893Sdim // (Y - X) + X -> Y 546218893Sdim // Eg: X + -X -> 0 547218893Sdim Value *Y = 0; 548218893Sdim if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) || 549218893Sdim match(Op0, m_Sub(m_Value(Y), m_Specific(Op1)))) 550218893Sdim return Y; 551218893Sdim 552218893Sdim // X + ~X -> -1 since ~X = -X-1 553218893Sdim if (match(Op0, m_Not(m_Specific(Op1))) || 554218893Sdim match(Op1, m_Not(m_Specific(Op0)))) 555218893Sdim return Constant::getAllOnesValue(Op0->getType()); 556218893Sdim 557218893Sdim /// i1 add -> xor. 558218893Sdim if (MaxRecurse && Op0->getType()->isIntegerTy(1)) 559218893Sdim if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1)) 560218893Sdim return V; 561218893Sdim 562218893Sdim // Try some generic simplifications for associative operations. 563218893Sdim if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, TD, DT, 564218893Sdim MaxRecurse)) 565218893Sdim return V; 566218893Sdim 567218893Sdim // Mul distributes over Add. Try some generic simplifications based on this. 568218893Sdim if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul, 569218893Sdim TD, DT, MaxRecurse)) 570218893Sdim return V; 571218893Sdim 572218893Sdim // Threading Add over selects and phi nodes is pointless, so don't bother. 573218893Sdim // Threading over the select in "A + select(cond, B, C)" means evaluating 574218893Sdim // "A+B" and "A+C" and seeing if they are equal; but they are equal if and 575218893Sdim // only if B and C are equal. If B and C are equal then (since we assume 576218893Sdim // that operands have already been simplified) "select(cond, B, C)" should 577218893Sdim // have been simplified to the common value of B and C already. Analysing 578218893Sdim // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly 579218893Sdim // for threading over phi nodes. 580218893Sdim 581218893Sdim return 0; 582218893Sdim} 583218893Sdim 584218893SdimValue *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 585218893Sdim const TargetData *TD, const DominatorTree *DT) { 586218893Sdim return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit); 587218893Sdim} 588218893Sdim 589218893Sdim/// SimplifySubInst - Given operands for a Sub, see if we can 590218893Sdim/// fold the result. If not, this returns null. 591218893Sdimstatic Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 592218893Sdim const TargetData *TD, const DominatorTree *DT, 593218893Sdim unsigned MaxRecurse) { 594218893Sdim if (Constant *CLHS = dyn_cast<Constant>(Op0)) 595218893Sdim if (Constant *CRHS = dyn_cast<Constant>(Op1)) { 596218893Sdim Constant *Ops[] = { CLHS, CRHS }; 597218893Sdim return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(), 598218893Sdim Ops, 2, TD); 599218893Sdim } 600218893Sdim 601218893Sdim // X - undef -> undef 602218893Sdim // undef - X -> undef 603218893Sdim if (match(Op0, m_Undef()) || match(Op1, m_Undef())) 604218893Sdim return UndefValue::get(Op0->getType()); 605218893Sdim 606218893Sdim // X - 0 -> X 607218893Sdim if (match(Op1, m_Zero())) 608218893Sdim return Op0; 609218893Sdim 610218893Sdim // X - X -> 0 611218893Sdim if (Op0 == Op1) 612218893Sdim return Constant::getNullValue(Op0->getType()); 613218893Sdim 614218893Sdim // (X*2) - X -> X 615218893Sdim // (X<<1) - X -> X 616218893Sdim Value *X = 0; 617218893Sdim if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) || 618218893Sdim match(Op0, m_Shl(m_Specific(Op1), m_One()))) 619218893Sdim return Op1; 620218893Sdim 621218893Sdim // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies. 622218893Sdim // For example, (X + Y) - Y -> X; (Y + X) - Y -> X 623218893Sdim Value *Y = 0, *Z = Op1; 624218893Sdim if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z 625218893Sdim // See if "V === Y - Z" simplifies. 626218893Sdim if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, TD, DT, MaxRecurse-1)) 627218893Sdim // It does! Now see if "X + V" simplifies. 628218893Sdim if (Value *W = SimplifyBinOp(Instruction::Add, X, V, TD, DT, 629218893Sdim MaxRecurse-1)) { 630218893Sdim // It does, we successfully reassociated! 631218893Sdim ++NumReassoc; 632218893Sdim return W; 633218893Sdim } 634218893Sdim // See if "V === X - Z" simplifies. 635218893Sdim if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, TD, DT, MaxRecurse-1)) 636218893Sdim // It does! Now see if "Y + V" simplifies. 637218893Sdim if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, TD, DT, 638218893Sdim MaxRecurse-1)) { 639218893Sdim // It does, we successfully reassociated! 640218893Sdim ++NumReassoc; 641218893Sdim return W; 642218893Sdim } 643199989Srdivacky } 644218893Sdim 645218893Sdim // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies. 646218893Sdim // For example, X - (X + 1) -> -1 647218893Sdim X = Op0; 648218893Sdim if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z) 649218893Sdim // See if "V === X - Y" simplifies. 650218893Sdim if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, TD, DT, MaxRecurse-1)) 651218893Sdim // It does! Now see if "V - Z" simplifies. 652218893Sdim if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, TD, DT, 653218893Sdim MaxRecurse-1)) { 654218893Sdim // It does, we successfully reassociated! 655218893Sdim ++NumReassoc; 656218893Sdim return W; 657218893Sdim } 658218893Sdim // See if "V === X - Z" simplifies. 659218893Sdim if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, TD, DT, MaxRecurse-1)) 660218893Sdim // It does! Now see if "V - Y" simplifies. 661218893Sdim if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, TD, DT, 662218893Sdim MaxRecurse-1)) { 663218893Sdim // It does, we successfully reassociated! 664218893Sdim ++NumReassoc; 665218893Sdim return W; 666218893Sdim } 667218893Sdim } 668218893Sdim 669218893Sdim // Z - (X - Y) -> (Z - X) + Y if everything simplifies. 670218893Sdim // For example, X - (X - Y) -> Y. 671218893Sdim Z = Op0; 672218893Sdim if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y) 673218893Sdim // See if "V === Z - X" simplifies. 674218893Sdim if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, TD, DT, MaxRecurse-1)) 675218893Sdim // It does! Now see if "V + Y" simplifies. 676218893Sdim if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, TD, DT, 677218893Sdim MaxRecurse-1)) { 678218893Sdim // It does, we successfully reassociated! 679218893Sdim ++NumReassoc; 680218893Sdim return W; 681218893Sdim } 682218893Sdim 683218893Sdim // Mul distributes over Sub. Try some generic simplifications based on this. 684218893Sdim if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul, 685218893Sdim TD, DT, MaxRecurse)) 686218893Sdim return V; 687218893Sdim 688218893Sdim // i1 sub -> xor. 689218893Sdim if (MaxRecurse && Op0->getType()->isIntegerTy(1)) 690218893Sdim if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1)) 691218893Sdim return V; 692218893Sdim 693218893Sdim // Threading Sub over selects and phi nodes is pointless, so don't bother. 694218893Sdim // Threading over the select in "A - select(cond, B, C)" means evaluating 695218893Sdim // "A-B" and "A-C" and seeing if they are equal; but they are equal if and 696218893Sdim // only if B and C are equal. If B and C are equal then (since we assume 697218893Sdim // that operands have already been simplified) "select(cond, B, C)" should 698218893Sdim // have been simplified to the common value of B and C already. Analysing 699218893Sdim // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly 700218893Sdim // for threading over phi nodes. 701218893Sdim 702199989Srdivacky return 0; 703199989Srdivacky} 704199989Srdivacky 705218893SdimValue *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 706218893Sdim const TargetData *TD, const DominatorTree *DT) { 707218893Sdim return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit); 708218893Sdim} 709218893Sdim 710218893Sdim/// SimplifyMulInst - Given operands for a Mul, see if we can 711218893Sdim/// fold the result. If not, this returns null. 712218893Sdimstatic Value *SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD, 713218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 714218893Sdim if (Constant *CLHS = dyn_cast<Constant>(Op0)) { 715218893Sdim if (Constant *CRHS = dyn_cast<Constant>(Op1)) { 716218893Sdim Constant *Ops[] = { CLHS, CRHS }; 717218893Sdim return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(), 718218893Sdim Ops, 2, TD); 719218893Sdim } 720218893Sdim 721218893Sdim // Canonicalize the constant to the RHS. 722218893Sdim std::swap(Op0, Op1); 723218893Sdim } 724218893Sdim 725218893Sdim // X * undef -> 0 726218893Sdim if (match(Op1, m_Undef())) 727218893Sdim return Constant::getNullValue(Op0->getType()); 728218893Sdim 729218893Sdim // X * 0 -> 0 730218893Sdim if (match(Op1, m_Zero())) 731218893Sdim return Op1; 732218893Sdim 733218893Sdim // X * 1 -> X 734218893Sdim if (match(Op1, m_One())) 735218893Sdim return Op0; 736218893Sdim 737218893Sdim // (X / Y) * Y -> X if the division is exact. 738218893Sdim Value *X = 0, *Y = 0; 739218893Sdim if ((match(Op0, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op1) || // (X / Y) * Y 740218893Sdim (match(Op1, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { // Y * (X / Y) 741218893Sdim BinaryOperator *Div = cast<BinaryOperator>(Y == Op1 ? Op0 : Op1); 742218893Sdim if (Div->isExact()) 743218893Sdim return X; 744218893Sdim } 745218893Sdim 746218893Sdim // i1 mul -> and. 747218893Sdim if (MaxRecurse && Op0->getType()->isIntegerTy(1)) 748218893Sdim if (Value *V = SimplifyAndInst(Op0, Op1, TD, DT, MaxRecurse-1)) 749218893Sdim return V; 750218893Sdim 751218893Sdim // Try some generic simplifications for associative operations. 752218893Sdim if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, TD, DT, 753218893Sdim MaxRecurse)) 754218893Sdim return V; 755218893Sdim 756218893Sdim // Mul distributes over Add. Try some generic simplifications based on this. 757218893Sdim if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add, 758218893Sdim TD, DT, MaxRecurse)) 759218893Sdim return V; 760218893Sdim 761218893Sdim // If the operation is with the result of a select instruction, check whether 762218893Sdim // operating on either branch of the select always yields the same value. 763218893Sdim if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 764218893Sdim if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, TD, DT, 765218893Sdim MaxRecurse)) 766218893Sdim return V; 767218893Sdim 768218893Sdim // If the operation is with the result of a phi instruction, check whether 769218893Sdim // operating on all incoming values of the phi always yields the same value. 770218893Sdim if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 771218893Sdim if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, TD, DT, 772218893Sdim MaxRecurse)) 773218893Sdim return V; 774218893Sdim 775218893Sdim return 0; 776218893Sdim} 777218893Sdim 778218893SdimValue *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD, 779218893Sdim const DominatorTree *DT) { 780218893Sdim return ::SimplifyMulInst(Op0, Op1, TD, DT, RecursionLimit); 781218893Sdim} 782218893Sdim 783218893Sdim/// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can 784218893Sdim/// fold the result. If not, this returns null. 785218893Sdimstatic Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, 786218893Sdim const TargetData *TD, const DominatorTree *DT, 787218893Sdim unsigned MaxRecurse) { 788218893Sdim if (Constant *C0 = dyn_cast<Constant>(Op0)) { 789218893Sdim if (Constant *C1 = dyn_cast<Constant>(Op1)) { 790218893Sdim Constant *Ops[] = { C0, C1 }; 791218893Sdim return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, 2, TD); 792218893Sdim } 793218893Sdim } 794218893Sdim 795218893Sdim bool isSigned = Opcode == Instruction::SDiv; 796218893Sdim 797218893Sdim // X / undef -> undef 798218893Sdim if (match(Op1, m_Undef())) 799218893Sdim return Op1; 800218893Sdim 801218893Sdim // undef / X -> 0 802218893Sdim if (match(Op0, m_Undef())) 803218893Sdim return Constant::getNullValue(Op0->getType()); 804218893Sdim 805218893Sdim // 0 / X -> 0, we don't need to preserve faults! 806218893Sdim if (match(Op0, m_Zero())) 807218893Sdim return Op0; 808218893Sdim 809218893Sdim // X / 1 -> X 810218893Sdim if (match(Op1, m_One())) 811218893Sdim return Op0; 812218893Sdim 813218893Sdim if (Op0->getType()->isIntegerTy(1)) 814218893Sdim // It can't be division by zero, hence it must be division by one. 815218893Sdim return Op0; 816218893Sdim 817218893Sdim // X / X -> 1 818218893Sdim if (Op0 == Op1) 819218893Sdim return ConstantInt::get(Op0->getType(), 1); 820218893Sdim 821218893Sdim // (X * Y) / Y -> X if the multiplication does not overflow. 822218893Sdim Value *X = 0, *Y = 0; 823218893Sdim if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) { 824218893Sdim if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1 825218893Sdim BinaryOperator *Mul = cast<BinaryOperator>(Op0); 826218893Sdim // If the Mul knows it does not overflow, then we are good to go. 827218893Sdim if ((isSigned && Mul->hasNoSignedWrap()) || 828218893Sdim (!isSigned && Mul->hasNoUnsignedWrap())) 829218893Sdim return X; 830218893Sdim // If X has the form X = A / Y then X * Y cannot overflow. 831218893Sdim if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X)) 832218893Sdim if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y) 833218893Sdim return X; 834218893Sdim } 835218893Sdim 836218893Sdim // (X rem Y) / Y -> 0 837218893Sdim if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) || 838218893Sdim (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1))))) 839218893Sdim return Constant::getNullValue(Op0->getType()); 840218893Sdim 841218893Sdim // If the operation is with the result of a select instruction, check whether 842218893Sdim // operating on either branch of the select always yields the same value. 843218893Sdim if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 844218893Sdim if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse)) 845218893Sdim return V; 846218893Sdim 847218893Sdim // If the operation is with the result of a phi instruction, check whether 848218893Sdim // operating on all incoming values of the phi always yields the same value. 849218893Sdim if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 850218893Sdim if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse)) 851218893Sdim return V; 852218893Sdim 853218893Sdim return 0; 854218893Sdim} 855218893Sdim 856218893Sdim/// SimplifySDivInst - Given operands for an SDiv, see if we can 857218893Sdim/// fold the result. If not, this returns null. 858218893Sdimstatic Value *SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD, 859218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 860218893Sdim if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, TD, DT, MaxRecurse)) 861218893Sdim return V; 862218893Sdim 863218893Sdim return 0; 864218893Sdim} 865218893Sdim 866218893SdimValue *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD, 867218893Sdim const DominatorTree *DT) { 868218893Sdim return ::SimplifySDivInst(Op0, Op1, TD, DT, RecursionLimit); 869218893Sdim} 870218893Sdim 871218893Sdim/// SimplifyUDivInst - Given operands for a UDiv, see if we can 872218893Sdim/// fold the result. If not, this returns null. 873218893Sdimstatic Value *SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD, 874218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 875218893Sdim if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, TD, DT, MaxRecurse)) 876218893Sdim return V; 877218893Sdim 878218893Sdim return 0; 879218893Sdim} 880218893Sdim 881218893SdimValue *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD, 882218893Sdim const DominatorTree *DT) { 883218893Sdim return ::SimplifyUDivInst(Op0, Op1, TD, DT, RecursionLimit); 884218893Sdim} 885218893Sdim 886218893Sdimstatic Value *SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *, 887218893Sdim const DominatorTree *, unsigned) { 888218893Sdim // undef / X -> undef (the undef could be a snan). 889218893Sdim if (match(Op0, m_Undef())) 890218893Sdim return Op0; 891218893Sdim 892218893Sdim // X / undef -> undef 893218893Sdim if (match(Op1, m_Undef())) 894218893Sdim return Op1; 895218893Sdim 896218893Sdim return 0; 897218893Sdim} 898218893Sdim 899218893SdimValue *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *TD, 900218893Sdim const DominatorTree *DT) { 901218893Sdim return ::SimplifyFDivInst(Op0, Op1, TD, DT, RecursionLimit); 902218893Sdim} 903218893Sdim 904221345Sdim/// SimplifyRem - Given operands for an SRem or URem, see if we can 905221345Sdim/// fold the result. If not, this returns null. 906221345Sdimstatic Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, 907221345Sdim const TargetData *TD, const DominatorTree *DT, 908221345Sdim unsigned MaxRecurse) { 909221345Sdim if (Constant *C0 = dyn_cast<Constant>(Op0)) { 910221345Sdim if (Constant *C1 = dyn_cast<Constant>(Op1)) { 911221345Sdim Constant *Ops[] = { C0, C1 }; 912221345Sdim return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, 2, TD); 913221345Sdim } 914221345Sdim } 915221345Sdim 916221345Sdim // X % undef -> undef 917221345Sdim if (match(Op1, m_Undef())) 918221345Sdim return Op1; 919221345Sdim 920221345Sdim // undef % X -> 0 921221345Sdim if (match(Op0, m_Undef())) 922221345Sdim return Constant::getNullValue(Op0->getType()); 923221345Sdim 924221345Sdim // 0 % X -> 0, we don't need to preserve faults! 925221345Sdim if (match(Op0, m_Zero())) 926221345Sdim return Op0; 927221345Sdim 928221345Sdim // X % 0 -> undef, we don't need to preserve faults! 929221345Sdim if (match(Op1, m_Zero())) 930221345Sdim return UndefValue::get(Op0->getType()); 931221345Sdim 932221345Sdim // X % 1 -> 0 933221345Sdim if (match(Op1, m_One())) 934221345Sdim return Constant::getNullValue(Op0->getType()); 935221345Sdim 936221345Sdim if (Op0->getType()->isIntegerTy(1)) 937221345Sdim // It can't be remainder by zero, hence it must be remainder by one. 938221345Sdim return Constant::getNullValue(Op0->getType()); 939221345Sdim 940221345Sdim // X % X -> 0 941221345Sdim if (Op0 == Op1) 942221345Sdim return Constant::getNullValue(Op0->getType()); 943221345Sdim 944221345Sdim // If the operation is with the result of a select instruction, check whether 945221345Sdim // operating on either branch of the select always yields the same value. 946221345Sdim if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 947221345Sdim if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse)) 948221345Sdim return V; 949221345Sdim 950221345Sdim // If the operation is with the result of a phi instruction, check whether 951221345Sdim // operating on all incoming values of the phi always yields the same value. 952221345Sdim if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 953221345Sdim if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse)) 954221345Sdim return V; 955221345Sdim 956221345Sdim return 0; 957221345Sdim} 958221345Sdim 959221345Sdim/// SimplifySRemInst - Given operands for an SRem, see if we can 960221345Sdim/// fold the result. If not, this returns null. 961221345Sdimstatic Value *SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD, 962221345Sdim const DominatorTree *DT, unsigned MaxRecurse) { 963221345Sdim if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, TD, DT, MaxRecurse)) 964221345Sdim return V; 965221345Sdim 966221345Sdim return 0; 967221345Sdim} 968221345Sdim 969221345SdimValue *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD, 970221345Sdim const DominatorTree *DT) { 971221345Sdim return ::SimplifySRemInst(Op0, Op1, TD, DT, RecursionLimit); 972221345Sdim} 973221345Sdim 974221345Sdim/// SimplifyURemInst - Given operands for a URem, see if we can 975221345Sdim/// fold the result. If not, this returns null. 976221345Sdimstatic Value *SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD, 977221345Sdim const DominatorTree *DT, unsigned MaxRecurse) { 978221345Sdim if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, TD, DT, MaxRecurse)) 979221345Sdim return V; 980221345Sdim 981221345Sdim return 0; 982221345Sdim} 983221345Sdim 984221345SdimValue *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD, 985221345Sdim const DominatorTree *DT) { 986221345Sdim return ::SimplifyURemInst(Op0, Op1, TD, DT, RecursionLimit); 987221345Sdim} 988221345Sdim 989221345Sdimstatic Value *SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *, 990221345Sdim const DominatorTree *, unsigned) { 991221345Sdim // undef % X -> undef (the undef could be a snan). 992221345Sdim if (match(Op0, m_Undef())) 993221345Sdim return Op0; 994221345Sdim 995221345Sdim // X % undef -> undef 996221345Sdim if (match(Op1, m_Undef())) 997221345Sdim return Op1; 998221345Sdim 999221345Sdim return 0; 1000221345Sdim} 1001221345Sdim 1002221345SdimValue *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *TD, 1003221345Sdim const DominatorTree *DT) { 1004221345Sdim return ::SimplifyFRemInst(Op0, Op1, TD, DT, RecursionLimit); 1005221345Sdim} 1006221345Sdim 1007218893Sdim/// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can 1008218893Sdim/// fold the result. If not, this returns null. 1009218893Sdimstatic Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1, 1010218893Sdim const TargetData *TD, const DominatorTree *DT, 1011218893Sdim unsigned MaxRecurse) { 1012218893Sdim if (Constant *C0 = dyn_cast<Constant>(Op0)) { 1013218893Sdim if (Constant *C1 = dyn_cast<Constant>(Op1)) { 1014218893Sdim Constant *Ops[] = { C0, C1 }; 1015218893Sdim return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, 2, TD); 1016218893Sdim } 1017218893Sdim } 1018218893Sdim 1019218893Sdim // 0 shift by X -> 0 1020218893Sdim if (match(Op0, m_Zero())) 1021218893Sdim return Op0; 1022218893Sdim 1023218893Sdim // X shift by 0 -> X 1024218893Sdim if (match(Op1, m_Zero())) 1025218893Sdim return Op0; 1026218893Sdim 1027218893Sdim // X shift by undef -> undef because it may shift by the bitwidth. 1028218893Sdim if (match(Op1, m_Undef())) 1029218893Sdim return Op1; 1030218893Sdim 1031218893Sdim // Shifting by the bitwidth or more is undefined. 1032218893Sdim if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) 1033218893Sdim if (CI->getValue().getLimitedValue() >= 1034218893Sdim Op0->getType()->getScalarSizeInBits()) 1035218893Sdim return UndefValue::get(Op0->getType()); 1036218893Sdim 1037218893Sdim // If the operation is with the result of a select instruction, check whether 1038218893Sdim // operating on either branch of the select always yields the same value. 1039218893Sdim if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 1040218893Sdim if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse)) 1041218893Sdim return V; 1042218893Sdim 1043218893Sdim // If the operation is with the result of a phi instruction, check whether 1044218893Sdim // operating on all incoming values of the phi always yields the same value. 1045218893Sdim if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 1046218893Sdim if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse)) 1047218893Sdim return V; 1048218893Sdim 1049218893Sdim return 0; 1050218893Sdim} 1051218893Sdim 1052218893Sdim/// SimplifyShlInst - Given operands for an Shl, see if we can 1053218893Sdim/// fold the result. If not, this returns null. 1054218893Sdimstatic Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 1055218893Sdim const TargetData *TD, const DominatorTree *DT, 1056218893Sdim unsigned MaxRecurse) { 1057218893Sdim if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, TD, DT, MaxRecurse)) 1058218893Sdim return V; 1059218893Sdim 1060218893Sdim // undef << X -> 0 1061218893Sdim if (match(Op0, m_Undef())) 1062218893Sdim return Constant::getNullValue(Op0->getType()); 1063218893Sdim 1064218893Sdim // (X >> A) << A -> X 1065218893Sdim Value *X; 1066218893Sdim if (match(Op0, m_Shr(m_Value(X), m_Specific(Op1))) && 1067218893Sdim cast<PossiblyExactOperator>(Op0)->isExact()) 1068218893Sdim return X; 1069218893Sdim return 0; 1070218893Sdim} 1071218893Sdim 1072218893SdimValue *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 1073218893Sdim const TargetData *TD, const DominatorTree *DT) { 1074218893Sdim return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit); 1075218893Sdim} 1076218893Sdim 1077218893Sdim/// SimplifyLShrInst - Given operands for an LShr, see if we can 1078218893Sdim/// fold the result. If not, this returns null. 1079218893Sdimstatic Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, 1080218893Sdim const TargetData *TD, const DominatorTree *DT, 1081218893Sdim unsigned MaxRecurse) { 1082218893Sdim if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, TD, DT, MaxRecurse)) 1083218893Sdim return V; 1084218893Sdim 1085218893Sdim // undef >>l X -> 0 1086218893Sdim if (match(Op0, m_Undef())) 1087218893Sdim return Constant::getNullValue(Op0->getType()); 1088218893Sdim 1089218893Sdim // (X << A) >> A -> X 1090218893Sdim Value *X; 1091218893Sdim if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) && 1092218893Sdim cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap()) 1093218893Sdim return X; 1094218893Sdim 1095218893Sdim return 0; 1096218893Sdim} 1097218893Sdim 1098218893SdimValue *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, 1099218893Sdim const TargetData *TD, const DominatorTree *DT) { 1100218893Sdim return ::SimplifyLShrInst(Op0, Op1, isExact, TD, DT, RecursionLimit); 1101218893Sdim} 1102218893Sdim 1103218893Sdim/// SimplifyAShrInst - Given operands for an AShr, see if we can 1104218893Sdim/// fold the result. If not, this returns null. 1105218893Sdimstatic Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, 1106218893Sdim const TargetData *TD, const DominatorTree *DT, 1107218893Sdim unsigned MaxRecurse) { 1108218893Sdim if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, TD, DT, MaxRecurse)) 1109218893Sdim return V; 1110218893Sdim 1111218893Sdim // all ones >>a X -> all ones 1112218893Sdim if (match(Op0, m_AllOnes())) 1113218893Sdim return Op0; 1114218893Sdim 1115218893Sdim // undef >>a X -> all ones 1116218893Sdim if (match(Op0, m_Undef())) 1117218893Sdim return Constant::getAllOnesValue(Op0->getType()); 1118218893Sdim 1119218893Sdim // (X << A) >> A -> X 1120218893Sdim Value *X; 1121218893Sdim if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) && 1122218893Sdim cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap()) 1123218893Sdim return X; 1124218893Sdim 1125218893Sdim return 0; 1126218893Sdim} 1127218893Sdim 1128218893SdimValue *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, 1129218893Sdim const TargetData *TD, const DominatorTree *DT) { 1130218893Sdim return ::SimplifyAShrInst(Op0, Op1, isExact, TD, DT, RecursionLimit); 1131218893Sdim} 1132218893Sdim 1133199989Srdivacky/// SimplifyAndInst - Given operands for an And, see if we can 1134199989Srdivacky/// fold the result. If not, this returns null. 1135218893Sdimstatic Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD, 1136218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 1137199989Srdivacky if (Constant *CLHS = dyn_cast<Constant>(Op0)) { 1138199989Srdivacky if (Constant *CRHS = dyn_cast<Constant>(Op1)) { 1139199989Srdivacky Constant *Ops[] = { CLHS, CRHS }; 1140199481Srdivacky return ConstantFoldInstOperands(Instruction::And, CLHS->getType(), 1141199481Srdivacky Ops, 2, TD); 1142199481Srdivacky } 1143218893Sdim 1144199481Srdivacky // Canonicalize the constant to the RHS. 1145199481Srdivacky std::swap(Op0, Op1); 1146199481Srdivacky } 1147218893Sdim 1148199481Srdivacky // X & undef -> 0 1149218893Sdim if (match(Op1, m_Undef())) 1150199481Srdivacky return Constant::getNullValue(Op0->getType()); 1151218893Sdim 1152199481Srdivacky // X & X = X 1153199481Srdivacky if (Op0 == Op1) 1154199481Srdivacky return Op0; 1155218893Sdim 1156218893Sdim // X & 0 = 0 1157218893Sdim if (match(Op1, m_Zero())) 1158199481Srdivacky return Op1; 1159218893Sdim 1160218893Sdim // X & -1 = X 1161218893Sdim if (match(Op1, m_AllOnes())) 1162218893Sdim return Op0; 1163218893Sdim 1164199481Srdivacky // A & ~A = ~A & A = 0 1165218893Sdim if (match(Op0, m_Not(m_Specific(Op1))) || 1166218893Sdim match(Op1, m_Not(m_Specific(Op0)))) 1167199481Srdivacky return Constant::getNullValue(Op0->getType()); 1168218893Sdim 1169199481Srdivacky // (A | ?) & A = A 1170218893Sdim Value *A = 0, *B = 0; 1171199481Srdivacky if (match(Op0, m_Or(m_Value(A), m_Value(B))) && 1172199481Srdivacky (A == Op1 || B == Op1)) 1173199481Srdivacky return Op1; 1174218893Sdim 1175199481Srdivacky // A & (A | ?) = A 1176199481Srdivacky if (match(Op1, m_Or(m_Value(A), m_Value(B))) && 1177199481Srdivacky (A == Op0 || B == Op0)) 1178199481Srdivacky return Op0; 1179218893Sdim 1180218893Sdim // Try some generic simplifications for associative operations. 1181218893Sdim if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, TD, DT, 1182218893Sdim MaxRecurse)) 1183218893Sdim return V; 1184218893Sdim 1185218893Sdim // And distributes over Or. Try some generic simplifications based on this. 1186218893Sdim if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or, 1187218893Sdim TD, DT, MaxRecurse)) 1188218893Sdim return V; 1189218893Sdim 1190218893Sdim // And distributes over Xor. Try some generic simplifications based on this. 1191218893Sdim if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor, 1192218893Sdim TD, DT, MaxRecurse)) 1193218893Sdim return V; 1194218893Sdim 1195218893Sdim // Or distributes over And. Try some generic simplifications based on this. 1196218893Sdim if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or, 1197218893Sdim TD, DT, MaxRecurse)) 1198218893Sdim return V; 1199218893Sdim 1200218893Sdim // If the operation is with the result of a select instruction, check whether 1201218893Sdim // operating on either branch of the select always yields the same value. 1202218893Sdim if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 1203218893Sdim if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, TD, DT, 1204218893Sdim MaxRecurse)) 1205218893Sdim return V; 1206218893Sdim 1207218893Sdim // If the operation is with the result of a phi instruction, check whether 1208218893Sdim // operating on all incoming values of the phi always yields the same value. 1209218893Sdim if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 1210218893Sdim if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, TD, DT, 1211218893Sdim MaxRecurse)) 1212218893Sdim return V; 1213218893Sdim 1214199481Srdivacky return 0; 1215199481Srdivacky} 1216199481Srdivacky 1217218893SdimValue *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD, 1218218893Sdim const DominatorTree *DT) { 1219218893Sdim return ::SimplifyAndInst(Op0, Op1, TD, DT, RecursionLimit); 1220218893Sdim} 1221218893Sdim 1222199481Srdivacky/// SimplifyOrInst - Given operands for an Or, see if we can 1223199481Srdivacky/// fold the result. If not, this returns null. 1224218893Sdimstatic Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD, 1225218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 1226199481Srdivacky if (Constant *CLHS = dyn_cast<Constant>(Op0)) { 1227199481Srdivacky if (Constant *CRHS = dyn_cast<Constant>(Op1)) { 1228199481Srdivacky Constant *Ops[] = { CLHS, CRHS }; 1229199481Srdivacky return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(), 1230199481Srdivacky Ops, 2, TD); 1231199481Srdivacky } 1232218893Sdim 1233199481Srdivacky // Canonicalize the constant to the RHS. 1234199481Srdivacky std::swap(Op0, Op1); 1235199481Srdivacky } 1236218893Sdim 1237199481Srdivacky // X | undef -> -1 1238218893Sdim if (match(Op1, m_Undef())) 1239199481Srdivacky return Constant::getAllOnesValue(Op0->getType()); 1240218893Sdim 1241199481Srdivacky // X | X = X 1242199481Srdivacky if (Op0 == Op1) 1243199481Srdivacky return Op0; 1244199481Srdivacky 1245218893Sdim // X | 0 = X 1246218893Sdim if (match(Op1, m_Zero())) 1247199481Srdivacky return Op0; 1248218893Sdim 1249218893Sdim // X | -1 = -1 1250218893Sdim if (match(Op1, m_AllOnes())) 1251218893Sdim return Op1; 1252218893Sdim 1253199481Srdivacky // A | ~A = ~A | A = -1 1254218893Sdim if (match(Op0, m_Not(m_Specific(Op1))) || 1255218893Sdim match(Op1, m_Not(m_Specific(Op0)))) 1256199481Srdivacky return Constant::getAllOnesValue(Op0->getType()); 1257218893Sdim 1258199481Srdivacky // (A & ?) | A = A 1259218893Sdim Value *A = 0, *B = 0; 1260199481Srdivacky if (match(Op0, m_And(m_Value(A), m_Value(B))) && 1261199481Srdivacky (A == Op1 || B == Op1)) 1262199481Srdivacky return Op1; 1263218893Sdim 1264199481Srdivacky // A | (A & ?) = A 1265199481Srdivacky if (match(Op1, m_And(m_Value(A), m_Value(B))) && 1266199481Srdivacky (A == Op0 || B == Op0)) 1267199481Srdivacky return Op0; 1268218893Sdim 1269219077Sdim // ~(A & ?) | A = -1 1270219077Sdim if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) && 1271219077Sdim (A == Op1 || B == Op1)) 1272219077Sdim return Constant::getAllOnesValue(Op1->getType()); 1273219077Sdim 1274219077Sdim // A | ~(A & ?) = -1 1275219077Sdim if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) && 1276219077Sdim (A == Op0 || B == Op0)) 1277219077Sdim return Constant::getAllOnesValue(Op0->getType()); 1278219077Sdim 1279218893Sdim // Try some generic simplifications for associative operations. 1280218893Sdim if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, TD, DT, 1281218893Sdim MaxRecurse)) 1282218893Sdim return V; 1283218893Sdim 1284218893Sdim // Or distributes over And. Try some generic simplifications based on this. 1285218893Sdim if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, 1286218893Sdim TD, DT, MaxRecurse)) 1287218893Sdim return V; 1288218893Sdim 1289218893Sdim // And distributes over Or. Try some generic simplifications based on this. 1290218893Sdim if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And, 1291218893Sdim TD, DT, MaxRecurse)) 1292218893Sdim return V; 1293218893Sdim 1294218893Sdim // If the operation is with the result of a select instruction, check whether 1295218893Sdim // operating on either branch of the select always yields the same value. 1296218893Sdim if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 1297218893Sdim if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, TD, DT, 1298218893Sdim MaxRecurse)) 1299218893Sdim return V; 1300218893Sdim 1301218893Sdim // If the operation is with the result of a phi instruction, check whether 1302218893Sdim // operating on all incoming values of the phi always yields the same value. 1303218893Sdim if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 1304218893Sdim if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, TD, DT, 1305218893Sdim MaxRecurse)) 1306218893Sdim return V; 1307218893Sdim 1308199481Srdivacky return 0; 1309199481Srdivacky} 1310199481Srdivacky 1311218893SdimValue *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD, 1312218893Sdim const DominatorTree *DT) { 1313218893Sdim return ::SimplifyOrInst(Op0, Op1, TD, DT, RecursionLimit); 1314218893Sdim} 1315199481Srdivacky 1316218893Sdim/// SimplifyXorInst - Given operands for a Xor, see if we can 1317218893Sdim/// fold the result. If not, this returns null. 1318218893Sdimstatic Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD, 1319218893Sdim const DominatorTree *DT, unsigned MaxRecurse) { 1320218893Sdim if (Constant *CLHS = dyn_cast<Constant>(Op0)) { 1321218893Sdim if (Constant *CRHS = dyn_cast<Constant>(Op1)) { 1322218893Sdim Constant *Ops[] = { CLHS, CRHS }; 1323218893Sdim return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(), 1324218893Sdim Ops, 2, TD); 1325218893Sdim } 1326218893Sdim 1327218893Sdim // Canonicalize the constant to the RHS. 1328218893Sdim std::swap(Op0, Op1); 1329218893Sdim } 1330218893Sdim 1331218893Sdim // A ^ undef -> undef 1332218893Sdim if (match(Op1, m_Undef())) 1333218893Sdim return Op1; 1334218893Sdim 1335218893Sdim // A ^ 0 = A 1336218893Sdim if (match(Op1, m_Zero())) 1337218893Sdim return Op0; 1338218893Sdim 1339218893Sdim // A ^ A = 0 1340218893Sdim if (Op0 == Op1) 1341218893Sdim return Constant::getNullValue(Op0->getType()); 1342218893Sdim 1343218893Sdim // A ^ ~A = ~A ^ A = -1 1344218893Sdim if (match(Op0, m_Not(m_Specific(Op1))) || 1345218893Sdim match(Op1, m_Not(m_Specific(Op0)))) 1346218893Sdim return Constant::getAllOnesValue(Op0->getType()); 1347218893Sdim 1348218893Sdim // Try some generic simplifications for associative operations. 1349218893Sdim if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, TD, DT, 1350218893Sdim MaxRecurse)) 1351218893Sdim return V; 1352218893Sdim 1353218893Sdim // And distributes over Xor. Try some generic simplifications based on this. 1354218893Sdim if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And, 1355218893Sdim TD, DT, MaxRecurse)) 1356218893Sdim return V; 1357218893Sdim 1358218893Sdim // Threading Xor over selects and phi nodes is pointless, so don't bother. 1359218893Sdim // Threading over the select in "A ^ select(cond, B, C)" means evaluating 1360218893Sdim // "A^B" and "A^C" and seeing if they are equal; but they are equal if and 1361218893Sdim // only if B and C are equal. If B and C are equal then (since we assume 1362218893Sdim // that operands have already been simplified) "select(cond, B, C)" should 1363218893Sdim // have been simplified to the common value of B and C already. Analysing 1364218893Sdim // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly 1365218893Sdim // for threading over phi nodes. 1366218893Sdim 1367218893Sdim return 0; 1368218893Sdim} 1369218893Sdim 1370218893SdimValue *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD, 1371218893Sdim const DominatorTree *DT) { 1372218893Sdim return ::SimplifyXorInst(Op0, Op1, TD, DT, RecursionLimit); 1373218893Sdim} 1374218893Sdim 1375199481Srdivackystatic const Type *GetCompareTy(Value *Op) { 1376199481Srdivacky return CmpInst::makeCmpResultType(Op->getType()); 1377199481Srdivacky} 1378199481Srdivacky 1379223017Sdim/// ExtractEquivalentCondition - Rummage around inside V looking for something 1380223017Sdim/// equivalent to the comparison "LHS Pred RHS". Return such a value if found, 1381223017Sdim/// otherwise return null. Helper function for analyzing max/min idioms. 1382223017Sdimstatic Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred, 1383223017Sdim Value *LHS, Value *RHS) { 1384223017Sdim SelectInst *SI = dyn_cast<SelectInst>(V); 1385223017Sdim if (!SI) 1386223017Sdim return 0; 1387223017Sdim CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition()); 1388223017Sdim if (!Cmp) 1389223017Sdim return 0; 1390223017Sdim Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1); 1391223017Sdim if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS) 1392223017Sdim return Cmp; 1393223017Sdim if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) && 1394223017Sdim LHS == CmpRHS && RHS == CmpLHS) 1395223017Sdim return Cmp; 1396223017Sdim return 0; 1397223017Sdim} 1398223017Sdim 1399199481Srdivacky/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can 1400199481Srdivacky/// fold the result. If not, this returns null. 1401218893Sdimstatic Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 1402218893Sdim const TargetData *TD, const DominatorTree *DT, 1403218893Sdim unsigned MaxRecurse) { 1404199481Srdivacky CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; 1405199481Srdivacky assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!"); 1406218893Sdim 1407199481Srdivacky if (Constant *CLHS = dyn_cast<Constant>(LHS)) { 1408199481Srdivacky if (Constant *CRHS = dyn_cast<Constant>(RHS)) 1409199481Srdivacky return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD); 1410199481Srdivacky 1411199481Srdivacky // If we have a constant, make sure it is on the RHS. 1412199481Srdivacky std::swap(LHS, RHS); 1413199481Srdivacky Pred = CmpInst::getSwappedPredicate(Pred); 1414199481Srdivacky } 1415218893Sdim 1416218893Sdim const Type *ITy = GetCompareTy(LHS); // The return type. 1417218893Sdim const Type *OpTy = LHS->getType(); // The operand type. 1418218893Sdim 1419199481Srdivacky // icmp X, X -> true/false 1420204792Srdivacky // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false 1421204792Srdivacky // because X could be 0. 1422204792Srdivacky if (LHS == RHS || isa<UndefValue>(RHS)) 1423199481Srdivacky return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred)); 1424218893Sdim 1425218893Sdim // Special case logic when the operands have i1 type. 1426218893Sdim if (OpTy->isIntegerTy(1) || (OpTy->isVectorTy() && 1427218893Sdim cast<VectorType>(OpTy)->getElementType()->isIntegerTy(1))) { 1428218893Sdim switch (Pred) { 1429218893Sdim default: break; 1430218893Sdim case ICmpInst::ICMP_EQ: 1431218893Sdim // X == 1 -> X 1432218893Sdim if (match(RHS, m_One())) 1433218893Sdim return LHS; 1434218893Sdim break; 1435218893Sdim case ICmpInst::ICMP_NE: 1436218893Sdim // X != 0 -> X 1437218893Sdim if (match(RHS, m_Zero())) 1438218893Sdim return LHS; 1439218893Sdim break; 1440218893Sdim case ICmpInst::ICMP_UGT: 1441218893Sdim // X >u 0 -> X 1442218893Sdim if (match(RHS, m_Zero())) 1443218893Sdim return LHS; 1444218893Sdim break; 1445218893Sdim case ICmpInst::ICMP_UGE: 1446218893Sdim // X >=u 1 -> X 1447218893Sdim if (match(RHS, m_One())) 1448218893Sdim return LHS; 1449218893Sdim break; 1450218893Sdim case ICmpInst::ICMP_SLT: 1451218893Sdim // X <s 0 -> X 1452218893Sdim if (match(RHS, m_Zero())) 1453218893Sdim return LHS; 1454218893Sdim break; 1455218893Sdim case ICmpInst::ICMP_SLE: 1456218893Sdim // X <=s -1 -> X 1457218893Sdim if (match(RHS, m_One())) 1458218893Sdim return LHS; 1459218893Sdim break; 1460218893Sdim } 1461218893Sdim } 1462218893Sdim 1463218893Sdim // icmp <alloca*>, <global/alloca*/null> - Different stack variables have 1464218893Sdim // different addresses, and what's more the address of a stack variable is 1465218893Sdim // never null or equal to the address of a global. Note that generalizing 1466218893Sdim // to the case where LHS is a global variable address or null is pointless, 1467218893Sdim // since if both LHS and RHS are constants then we already constant folded 1468218893Sdim // the compare, and if only one of them is then we moved it to RHS already. 1469218893Sdim if (isa<AllocaInst>(LHS) && (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) || 1470218893Sdim isa<ConstantPointerNull>(RHS))) 1471221345Sdim // We already know that LHS != RHS. 1472199481Srdivacky return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred)); 1473218893Sdim 1474218893Sdim // If we are comparing with zero then try hard since this is a common case. 1475218893Sdim if (match(RHS, m_Zero())) { 1476218893Sdim bool LHSKnownNonNegative, LHSKnownNegative; 1477199481Srdivacky switch (Pred) { 1478218893Sdim default: 1479218893Sdim assert(false && "Unknown ICmp predicate!"); 1480218893Sdim case ICmpInst::ICMP_ULT: 1481223017Sdim // getNullValue also works for vectors, unlike getFalse. 1482223017Sdim return Constant::getNullValue(ITy); 1483218893Sdim case ICmpInst::ICMP_UGE: 1484223017Sdim // getAllOnesValue also works for vectors, unlike getTrue. 1485223017Sdim return ConstantInt::getAllOnesValue(ITy); 1486218893Sdim case ICmpInst::ICMP_EQ: 1487199481Srdivacky case ICmpInst::ICMP_ULE: 1488218893Sdim if (isKnownNonZero(LHS, TD)) 1489223017Sdim return Constant::getNullValue(ITy); 1490199481Srdivacky break; 1491218893Sdim case ICmpInst::ICMP_NE: 1492218893Sdim case ICmpInst::ICMP_UGT: 1493218893Sdim if (isKnownNonZero(LHS, TD)) 1494223017Sdim return ConstantInt::getAllOnesValue(ITy); 1495218893Sdim break; 1496218893Sdim case ICmpInst::ICMP_SLT: 1497218893Sdim ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD); 1498218893Sdim if (LHSKnownNegative) 1499223017Sdim return ConstantInt::getAllOnesValue(ITy); 1500218893Sdim if (LHSKnownNonNegative) 1501223017Sdim return Constant::getNullValue(ITy); 1502218893Sdim break; 1503199481Srdivacky case ICmpInst::ICMP_SLE: 1504218893Sdim ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD); 1505218893Sdim if (LHSKnownNegative) 1506223017Sdim return ConstantInt::getAllOnesValue(ITy); 1507218893Sdim if (LHSKnownNonNegative && isKnownNonZero(LHS, TD)) 1508223017Sdim return Constant::getNullValue(ITy); 1509199481Srdivacky break; 1510218893Sdim case ICmpInst::ICMP_SGE: 1511218893Sdim ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD); 1512218893Sdim if (LHSKnownNegative) 1513223017Sdim return Constant::getNullValue(ITy); 1514218893Sdim if (LHSKnownNonNegative) 1515223017Sdim return ConstantInt::getAllOnesValue(ITy); 1516218893Sdim break; 1517218893Sdim case ICmpInst::ICMP_SGT: 1518218893Sdim ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD); 1519218893Sdim if (LHSKnownNegative) 1520223017Sdim return Constant::getNullValue(ITy); 1521218893Sdim if (LHSKnownNonNegative && isKnownNonZero(LHS, TD)) 1522223017Sdim return ConstantInt::getAllOnesValue(ITy); 1523218893Sdim break; 1524218893Sdim } 1525218893Sdim } 1526218893Sdim 1527218893Sdim // See if we are doing a comparison with a constant integer. 1528218893Sdim if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { 1529221345Sdim // Rule out tautological comparisons (eg., ult 0 or uge 0). 1530221345Sdim ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue()); 1531221345Sdim if (RHS_CR.isEmptySet()) 1532221345Sdim return ConstantInt::getFalse(CI->getContext()); 1533221345Sdim if (RHS_CR.isFullSet()) 1534221345Sdim return ConstantInt::getTrue(CI->getContext()); 1535221345Sdim 1536221345Sdim // Many binary operators with constant RHS have easy to compute constant 1537221345Sdim // range. Use them to check whether the comparison is a tautology. 1538221345Sdim uint32_t Width = CI->getBitWidth(); 1539221345Sdim APInt Lower = APInt(Width, 0); 1540221345Sdim APInt Upper = APInt(Width, 0); 1541221345Sdim ConstantInt *CI2; 1542221345Sdim if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) { 1543221345Sdim // 'urem x, CI2' produces [0, CI2). 1544221345Sdim Upper = CI2->getValue(); 1545221345Sdim } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) { 1546221345Sdim // 'srem x, CI2' produces (-|CI2|, |CI2|). 1547221345Sdim Upper = CI2->getValue().abs(); 1548221345Sdim Lower = (-Upper) + 1; 1549221345Sdim } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) { 1550221345Sdim // 'udiv x, CI2' produces [0, UINT_MAX / CI2]. 1551221345Sdim APInt NegOne = APInt::getAllOnesValue(Width); 1552221345Sdim if (!CI2->isZero()) 1553221345Sdim Upper = NegOne.udiv(CI2->getValue()) + 1; 1554221345Sdim } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) { 1555221345Sdim // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]. 1556221345Sdim APInt IntMin = APInt::getSignedMinValue(Width); 1557221345Sdim APInt IntMax = APInt::getSignedMaxValue(Width); 1558221345Sdim APInt Val = CI2->getValue().abs(); 1559221345Sdim if (!Val.isMinValue()) { 1560221345Sdim Lower = IntMin.sdiv(Val); 1561221345Sdim Upper = IntMax.sdiv(Val) + 1; 1562221345Sdim } 1563221345Sdim } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) { 1564221345Sdim // 'lshr x, CI2' produces [0, UINT_MAX >> CI2]. 1565221345Sdim APInt NegOne = APInt::getAllOnesValue(Width); 1566221345Sdim if (CI2->getValue().ult(Width)) 1567221345Sdim Upper = NegOne.lshr(CI2->getValue()) + 1; 1568221345Sdim } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) { 1569221345Sdim // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2]. 1570221345Sdim APInt IntMin = APInt::getSignedMinValue(Width); 1571221345Sdim APInt IntMax = APInt::getSignedMaxValue(Width); 1572221345Sdim if (CI2->getValue().ult(Width)) { 1573221345Sdim Lower = IntMin.ashr(CI2->getValue()); 1574221345Sdim Upper = IntMax.ashr(CI2->getValue()) + 1; 1575221345Sdim } 1576221345Sdim } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) { 1577221345Sdim // 'or x, CI2' produces [CI2, UINT_MAX]. 1578221345Sdim Lower = CI2->getValue(); 1579221345Sdim } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) { 1580221345Sdim // 'and x, CI2' produces [0, CI2]. 1581221345Sdim Upper = CI2->getValue() + 1; 1582199481Srdivacky } 1583221345Sdim if (Lower != Upper) { 1584221345Sdim ConstantRange LHS_CR = ConstantRange(Lower, Upper); 1585221345Sdim if (RHS_CR.contains(LHS_CR)) 1586221345Sdim return ConstantInt::getTrue(RHS->getContext()); 1587221345Sdim if (RHS_CR.inverse().contains(LHS_CR)) 1588221345Sdim return ConstantInt::getFalse(RHS->getContext()); 1589221345Sdim } 1590199481Srdivacky } 1591218893Sdim 1592218893Sdim // Compare of cast, for example (zext X) != 0 -> X != 0 1593218893Sdim if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) { 1594218893Sdim Instruction *LI = cast<CastInst>(LHS); 1595218893Sdim Value *SrcOp = LI->getOperand(0); 1596218893Sdim const Type *SrcTy = SrcOp->getType(); 1597218893Sdim const Type *DstTy = LI->getType(); 1598218893Sdim 1599218893Sdim // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input 1600218893Sdim // if the integer type is the same size as the pointer type. 1601218893Sdim if (MaxRecurse && TD && isa<PtrToIntInst>(LI) && 1602218893Sdim TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) { 1603218893Sdim if (Constant *RHSC = dyn_cast<Constant>(RHS)) { 1604218893Sdim // Transfer the cast to the constant. 1605218893Sdim if (Value *V = SimplifyICmpInst(Pred, SrcOp, 1606218893Sdim ConstantExpr::getIntToPtr(RHSC, SrcTy), 1607218893Sdim TD, DT, MaxRecurse-1)) 1608218893Sdim return V; 1609218893Sdim } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) { 1610218893Sdim if (RI->getOperand(0)->getType() == SrcTy) 1611218893Sdim // Compare without the cast. 1612218893Sdim if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0), 1613218893Sdim TD, DT, MaxRecurse-1)) 1614218893Sdim return V; 1615218893Sdim } 1616218893Sdim } 1617218893Sdim 1618218893Sdim if (isa<ZExtInst>(LHS)) { 1619218893Sdim // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the 1620218893Sdim // same type. 1621218893Sdim if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) { 1622218893Sdim if (MaxRecurse && SrcTy == RI->getOperand(0)->getType()) 1623218893Sdim // Compare X and Y. Note that signed predicates become unsigned. 1624218893Sdim if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred), 1625218893Sdim SrcOp, RI->getOperand(0), TD, DT, 1626218893Sdim MaxRecurse-1)) 1627218893Sdim return V; 1628218893Sdim } 1629218893Sdim // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended 1630218893Sdim // too. If not, then try to deduce the result of the comparison. 1631218893Sdim else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { 1632218893Sdim // Compute the constant that would happen if we truncated to SrcTy then 1633218893Sdim // reextended to DstTy. 1634218893Sdim Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy); 1635218893Sdim Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy); 1636218893Sdim 1637218893Sdim // If the re-extended constant didn't change then this is effectively 1638218893Sdim // also a case of comparing two zero-extended values. 1639218893Sdim if (RExt == CI && MaxRecurse) 1640218893Sdim if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred), 1641218893Sdim SrcOp, Trunc, TD, DT, MaxRecurse-1)) 1642218893Sdim return V; 1643218893Sdim 1644218893Sdim // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit 1645218893Sdim // there. Use this to work out the result of the comparison. 1646218893Sdim if (RExt != CI) { 1647218893Sdim switch (Pred) { 1648218893Sdim default: 1649218893Sdim assert(false && "Unknown ICmp predicate!"); 1650218893Sdim // LHS <u RHS. 1651218893Sdim case ICmpInst::ICMP_EQ: 1652218893Sdim case ICmpInst::ICMP_UGT: 1653218893Sdim case ICmpInst::ICMP_UGE: 1654218893Sdim return ConstantInt::getFalse(CI->getContext()); 1655218893Sdim 1656218893Sdim case ICmpInst::ICMP_NE: 1657218893Sdim case ICmpInst::ICMP_ULT: 1658218893Sdim case ICmpInst::ICMP_ULE: 1659218893Sdim return ConstantInt::getTrue(CI->getContext()); 1660218893Sdim 1661218893Sdim // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS 1662218893Sdim // is non-negative then LHS <s RHS. 1663218893Sdim case ICmpInst::ICMP_SGT: 1664218893Sdim case ICmpInst::ICMP_SGE: 1665218893Sdim return CI->getValue().isNegative() ? 1666218893Sdim ConstantInt::getTrue(CI->getContext()) : 1667218893Sdim ConstantInt::getFalse(CI->getContext()); 1668218893Sdim 1669218893Sdim case ICmpInst::ICMP_SLT: 1670218893Sdim case ICmpInst::ICMP_SLE: 1671218893Sdim return CI->getValue().isNegative() ? 1672218893Sdim ConstantInt::getFalse(CI->getContext()) : 1673218893Sdim ConstantInt::getTrue(CI->getContext()); 1674218893Sdim } 1675218893Sdim } 1676218893Sdim } 1677218893Sdim } 1678218893Sdim 1679218893Sdim if (isa<SExtInst>(LHS)) { 1680218893Sdim // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the 1681218893Sdim // same type. 1682218893Sdim if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) { 1683218893Sdim if (MaxRecurse && SrcTy == RI->getOperand(0)->getType()) 1684218893Sdim // Compare X and Y. Note that the predicate does not change. 1685218893Sdim if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0), 1686218893Sdim TD, DT, MaxRecurse-1)) 1687218893Sdim return V; 1688218893Sdim } 1689218893Sdim // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended 1690218893Sdim // too. If not, then try to deduce the result of the comparison. 1691218893Sdim else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { 1692218893Sdim // Compute the constant that would happen if we truncated to SrcTy then 1693218893Sdim // reextended to DstTy. 1694218893Sdim Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy); 1695218893Sdim Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy); 1696218893Sdim 1697218893Sdim // If the re-extended constant didn't change then this is effectively 1698218893Sdim // also a case of comparing two sign-extended values. 1699218893Sdim if (RExt == CI && MaxRecurse) 1700218893Sdim if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, TD, DT, 1701218893Sdim MaxRecurse-1)) 1702218893Sdim return V; 1703218893Sdim 1704218893Sdim // Otherwise the upper bits of LHS are all equal, while RHS has varying 1705218893Sdim // bits there. Use this to work out the result of the comparison. 1706218893Sdim if (RExt != CI) { 1707218893Sdim switch (Pred) { 1708218893Sdim default: 1709218893Sdim assert(false && "Unknown ICmp predicate!"); 1710218893Sdim case ICmpInst::ICMP_EQ: 1711218893Sdim return ConstantInt::getFalse(CI->getContext()); 1712218893Sdim case ICmpInst::ICMP_NE: 1713218893Sdim return ConstantInt::getTrue(CI->getContext()); 1714218893Sdim 1715218893Sdim // If RHS is non-negative then LHS <s RHS. If RHS is negative then 1716218893Sdim // LHS >s RHS. 1717218893Sdim case ICmpInst::ICMP_SGT: 1718218893Sdim case ICmpInst::ICMP_SGE: 1719218893Sdim return CI->getValue().isNegative() ? 1720218893Sdim ConstantInt::getTrue(CI->getContext()) : 1721218893Sdim ConstantInt::getFalse(CI->getContext()); 1722218893Sdim case ICmpInst::ICMP_SLT: 1723218893Sdim case ICmpInst::ICMP_SLE: 1724218893Sdim return CI->getValue().isNegative() ? 1725218893Sdim ConstantInt::getFalse(CI->getContext()) : 1726218893Sdim ConstantInt::getTrue(CI->getContext()); 1727218893Sdim 1728218893Sdim // If LHS is non-negative then LHS <u RHS. If LHS is negative then 1729218893Sdim // LHS >u RHS. 1730218893Sdim case ICmpInst::ICMP_UGT: 1731218893Sdim case ICmpInst::ICMP_UGE: 1732218893Sdim // Comparison is true iff the LHS <s 0. 1733218893Sdim if (MaxRecurse) 1734218893Sdim if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp, 1735218893Sdim Constant::getNullValue(SrcTy), 1736218893Sdim TD, DT, MaxRecurse-1)) 1737218893Sdim return V; 1738218893Sdim break; 1739218893Sdim case ICmpInst::ICMP_ULT: 1740218893Sdim case ICmpInst::ICMP_ULE: 1741218893Sdim // Comparison is true iff the LHS >=s 0. 1742218893Sdim if (MaxRecurse) 1743218893Sdim if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp, 1744218893Sdim Constant::getNullValue(SrcTy), 1745218893Sdim TD, DT, MaxRecurse-1)) 1746218893Sdim return V; 1747218893Sdim break; 1748218893Sdim } 1749218893Sdim } 1750218893Sdim } 1751218893Sdim } 1752218893Sdim } 1753218893Sdim 1754218893Sdim // Special logic for binary operators. 1755218893Sdim BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS); 1756218893Sdim BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS); 1757218893Sdim if (MaxRecurse && (LBO || RBO)) { 1758218893Sdim // Analyze the case when either LHS or RHS is an add instruction. 1759218893Sdim Value *A = 0, *B = 0, *C = 0, *D = 0; 1760218893Sdim // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null). 1761218893Sdim bool NoLHSWrapProblem = false, NoRHSWrapProblem = false; 1762218893Sdim if (LBO && LBO->getOpcode() == Instruction::Add) { 1763218893Sdim A = LBO->getOperand(0); B = LBO->getOperand(1); 1764218893Sdim NoLHSWrapProblem = ICmpInst::isEquality(Pred) || 1765218893Sdim (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) || 1766218893Sdim (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap()); 1767218893Sdim } 1768218893Sdim if (RBO && RBO->getOpcode() == Instruction::Add) { 1769218893Sdim C = RBO->getOperand(0); D = RBO->getOperand(1); 1770218893Sdim NoRHSWrapProblem = ICmpInst::isEquality(Pred) || 1771218893Sdim (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) || 1772218893Sdim (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap()); 1773218893Sdim } 1774218893Sdim 1775218893Sdim // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow. 1776218893Sdim if ((A == RHS || B == RHS) && NoLHSWrapProblem) 1777218893Sdim if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A, 1778218893Sdim Constant::getNullValue(RHS->getType()), 1779218893Sdim TD, DT, MaxRecurse-1)) 1780218893Sdim return V; 1781218893Sdim 1782218893Sdim // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow. 1783218893Sdim if ((C == LHS || D == LHS) && NoRHSWrapProblem) 1784218893Sdim if (Value *V = SimplifyICmpInst(Pred, 1785218893Sdim Constant::getNullValue(LHS->getType()), 1786218893Sdim C == LHS ? D : C, TD, DT, MaxRecurse-1)) 1787218893Sdim return V; 1788218893Sdim 1789218893Sdim // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow. 1790218893Sdim if (A && C && (A == C || A == D || B == C || B == D) && 1791218893Sdim NoLHSWrapProblem && NoRHSWrapProblem) { 1792218893Sdim // Determine Y and Z in the form icmp (X+Y), (X+Z). 1793218893Sdim Value *Y = (A == C || A == D) ? B : A; 1794218893Sdim Value *Z = (C == A || C == B) ? D : C; 1795218893Sdim if (Value *V = SimplifyICmpInst(Pred, Y, Z, TD, DT, MaxRecurse-1)) 1796218893Sdim return V; 1797218893Sdim } 1798218893Sdim } 1799218893Sdim 1800221345Sdim if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) { 1801221345Sdim bool KnownNonNegative, KnownNegative; 1802221345Sdim switch (Pred) { 1803221345Sdim default: 1804221345Sdim break; 1805221345Sdim case ICmpInst::ICMP_SGT: 1806221345Sdim case ICmpInst::ICMP_SGE: 1807221345Sdim ComputeSignBit(LHS, KnownNonNegative, KnownNegative, TD); 1808221345Sdim if (!KnownNonNegative) 1809221345Sdim break; 1810221345Sdim // fall-through 1811221345Sdim case ICmpInst::ICMP_EQ: 1812221345Sdim case ICmpInst::ICMP_UGT: 1813221345Sdim case ICmpInst::ICMP_UGE: 1814223017Sdim // getNullValue also works for vectors, unlike getFalse. 1815223017Sdim return Constant::getNullValue(ITy); 1816221345Sdim case ICmpInst::ICMP_SLT: 1817221345Sdim case ICmpInst::ICMP_SLE: 1818221345Sdim ComputeSignBit(LHS, KnownNonNegative, KnownNegative, TD); 1819221345Sdim if (!KnownNonNegative) 1820221345Sdim break; 1821221345Sdim // fall-through 1822221345Sdim case ICmpInst::ICMP_NE: 1823221345Sdim case ICmpInst::ICMP_ULT: 1824221345Sdim case ICmpInst::ICMP_ULE: 1825223017Sdim // getAllOnesValue also works for vectors, unlike getTrue. 1826223017Sdim return Constant::getAllOnesValue(ITy); 1827221345Sdim } 1828221345Sdim } 1829221345Sdim if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) { 1830221345Sdim bool KnownNonNegative, KnownNegative; 1831221345Sdim switch (Pred) { 1832221345Sdim default: 1833221345Sdim break; 1834221345Sdim case ICmpInst::ICMP_SGT: 1835221345Sdim case ICmpInst::ICMP_SGE: 1836221345Sdim ComputeSignBit(RHS, KnownNonNegative, KnownNegative, TD); 1837221345Sdim if (!KnownNonNegative) 1838221345Sdim break; 1839221345Sdim // fall-through 1840221345Sdim case ICmpInst::ICMP_NE: 1841221345Sdim case ICmpInst::ICMP_UGT: 1842221345Sdim case ICmpInst::ICMP_UGE: 1843223017Sdim // getAllOnesValue also works for vectors, unlike getTrue. 1844223017Sdim return Constant::getAllOnesValue(ITy); 1845221345Sdim case ICmpInst::ICMP_SLT: 1846221345Sdim case ICmpInst::ICMP_SLE: 1847221345Sdim ComputeSignBit(RHS, KnownNonNegative, KnownNegative, TD); 1848221345Sdim if (!KnownNonNegative) 1849221345Sdim break; 1850221345Sdim // fall-through 1851221345Sdim case ICmpInst::ICMP_EQ: 1852221345Sdim case ICmpInst::ICMP_ULT: 1853221345Sdim case ICmpInst::ICMP_ULE: 1854223017Sdim // getNullValue also works for vectors, unlike getFalse. 1855223017Sdim return Constant::getNullValue(ITy); 1856221345Sdim } 1857221345Sdim } 1858221345Sdim 1859221345Sdim if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() && 1860221345Sdim LBO->getOperand(1) == RBO->getOperand(1)) { 1861221345Sdim switch (LBO->getOpcode()) { 1862221345Sdim default: break; 1863221345Sdim case Instruction::UDiv: 1864221345Sdim case Instruction::LShr: 1865221345Sdim if (ICmpInst::isSigned(Pred)) 1866221345Sdim break; 1867221345Sdim // fall-through 1868221345Sdim case Instruction::SDiv: 1869221345Sdim case Instruction::AShr: 1870223017Sdim if (!LBO->isExact() || !RBO->isExact()) 1871221345Sdim break; 1872221345Sdim if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), 1873221345Sdim RBO->getOperand(0), TD, DT, MaxRecurse-1)) 1874221345Sdim return V; 1875221345Sdim break; 1876221345Sdim case Instruction::Shl: { 1877221345Sdim bool NUW = LBO->hasNoUnsignedWrap() && LBO->hasNoUnsignedWrap(); 1878221345Sdim bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap(); 1879221345Sdim if (!NUW && !NSW) 1880221345Sdim break; 1881221345Sdim if (!NSW && ICmpInst::isSigned(Pred)) 1882221345Sdim break; 1883221345Sdim if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), 1884221345Sdim RBO->getOperand(0), TD, DT, MaxRecurse-1)) 1885221345Sdim return V; 1886221345Sdim break; 1887221345Sdim } 1888221345Sdim } 1889221345Sdim } 1890221345Sdim 1891223017Sdim // Simplify comparisons involving max/min. 1892223017Sdim Value *A, *B; 1893223017Sdim CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE; 1894223017Sdim CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B". 1895223017Sdim 1896223017Sdim // Signed variants on "max(a,b)>=a -> true". 1897223017Sdim if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { 1898223017Sdim if (A != RHS) std::swap(A, B); // smax(A, B) pred A. 1899223017Sdim EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". 1900223017Sdim // We analyze this as smax(A, B) pred A. 1901223017Sdim P = Pred; 1902223017Sdim } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) && 1903223017Sdim (A == LHS || B == LHS)) { 1904223017Sdim if (A != LHS) std::swap(A, B); // A pred smax(A, B). 1905223017Sdim EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". 1906223017Sdim // We analyze this as smax(A, B) swapped-pred A. 1907223017Sdim P = CmpInst::getSwappedPredicate(Pred); 1908223017Sdim } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && 1909223017Sdim (A == RHS || B == RHS)) { 1910223017Sdim if (A != RHS) std::swap(A, B); // smin(A, B) pred A. 1911223017Sdim EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B". 1912223017Sdim // We analyze this as smax(-A, -B) swapped-pred -A. 1913223017Sdim // Note that we do not need to actually form -A or -B thanks to EqP. 1914223017Sdim P = CmpInst::getSwappedPredicate(Pred); 1915223017Sdim } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) && 1916223017Sdim (A == LHS || B == LHS)) { 1917223017Sdim if (A != LHS) std::swap(A, B); // A pred smin(A, B). 1918223017Sdim EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B". 1919223017Sdim // We analyze this as smax(-A, -B) pred -A. 1920223017Sdim // Note that we do not need to actually form -A or -B thanks to EqP. 1921223017Sdim P = Pred; 1922223017Sdim } 1923223017Sdim if (P != CmpInst::BAD_ICMP_PREDICATE) { 1924223017Sdim // Cases correspond to "max(A, B) p A". 1925223017Sdim switch (P) { 1926223017Sdim default: 1927223017Sdim break; 1928223017Sdim case CmpInst::ICMP_EQ: 1929223017Sdim case CmpInst::ICMP_SLE: 1930223017Sdim // Equivalent to "A EqP B". This may be the same as the condition tested 1931223017Sdim // in the max/min; if so, we can just return that. 1932223017Sdim if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B)) 1933223017Sdim return V; 1934223017Sdim if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B)) 1935223017Sdim return V; 1936223017Sdim // Otherwise, see if "A EqP B" simplifies. 1937223017Sdim if (MaxRecurse) 1938223017Sdim if (Value *V = SimplifyICmpInst(EqP, A, B, TD, DT, MaxRecurse-1)) 1939223017Sdim return V; 1940223017Sdim break; 1941223017Sdim case CmpInst::ICMP_NE: 1942223017Sdim case CmpInst::ICMP_SGT: { 1943223017Sdim CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP); 1944223017Sdim // Equivalent to "A InvEqP B". This may be the same as the condition 1945223017Sdim // tested in the max/min; if so, we can just return that. 1946223017Sdim if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B)) 1947223017Sdim return V; 1948223017Sdim if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B)) 1949223017Sdim return V; 1950223017Sdim // Otherwise, see if "A InvEqP B" simplifies. 1951223017Sdim if (MaxRecurse) 1952223017Sdim if (Value *V = SimplifyICmpInst(InvEqP, A, B, TD, DT, MaxRecurse-1)) 1953223017Sdim return V; 1954223017Sdim break; 1955223017Sdim } 1956223017Sdim case CmpInst::ICMP_SGE: 1957223017Sdim // Always true. 1958223017Sdim return Constant::getAllOnesValue(ITy); 1959223017Sdim case CmpInst::ICMP_SLT: 1960223017Sdim // Always false. 1961223017Sdim return Constant::getNullValue(ITy); 1962223017Sdim } 1963223017Sdim } 1964223017Sdim 1965223017Sdim // Unsigned variants on "max(a,b)>=a -> true". 1966223017Sdim P = CmpInst::BAD_ICMP_PREDICATE; 1967223017Sdim if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { 1968223017Sdim if (A != RHS) std::swap(A, B); // umax(A, B) pred A. 1969223017Sdim EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B". 1970223017Sdim // We analyze this as umax(A, B) pred A. 1971223017Sdim P = Pred; 1972223017Sdim } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) && 1973223017Sdim (A == LHS || B == LHS)) { 1974223017Sdim if (A != LHS) std::swap(A, B); // A pred umax(A, B). 1975223017Sdim EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B". 1976223017Sdim // We analyze this as umax(A, B) swapped-pred A. 1977223017Sdim P = CmpInst::getSwappedPredicate(Pred); 1978223017Sdim } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && 1979223017Sdim (A == RHS || B == RHS)) { 1980223017Sdim if (A != RHS) std::swap(A, B); // umin(A, B) pred A. 1981223017Sdim EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B". 1982223017Sdim // We analyze this as umax(-A, -B) swapped-pred -A. 1983223017Sdim // Note that we do not need to actually form -A or -B thanks to EqP. 1984223017Sdim P = CmpInst::getSwappedPredicate(Pred); 1985223017Sdim } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) && 1986223017Sdim (A == LHS || B == LHS)) { 1987223017Sdim if (A != LHS) std::swap(A, B); // A pred umin(A, B). 1988223017Sdim EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B". 1989223017Sdim // We analyze this as umax(-A, -B) pred -A. 1990223017Sdim // Note that we do not need to actually form -A or -B thanks to EqP. 1991223017Sdim P = Pred; 1992223017Sdim } 1993223017Sdim if (P != CmpInst::BAD_ICMP_PREDICATE) { 1994223017Sdim // Cases correspond to "max(A, B) p A". 1995223017Sdim switch (P) { 1996223017Sdim default: 1997223017Sdim break; 1998223017Sdim case CmpInst::ICMP_EQ: 1999223017Sdim case CmpInst::ICMP_ULE: 2000223017Sdim // Equivalent to "A EqP B". This may be the same as the condition tested 2001223017Sdim // in the max/min; if so, we can just return that. 2002223017Sdim if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B)) 2003223017Sdim return V; 2004223017Sdim if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B)) 2005223017Sdim return V; 2006223017Sdim // Otherwise, see if "A EqP B" simplifies. 2007223017Sdim if (MaxRecurse) 2008223017Sdim if (Value *V = SimplifyICmpInst(EqP, A, B, TD, DT, MaxRecurse-1)) 2009223017Sdim return V; 2010223017Sdim break; 2011223017Sdim case CmpInst::ICMP_NE: 2012223017Sdim case CmpInst::ICMP_UGT: { 2013223017Sdim CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP); 2014223017Sdim // Equivalent to "A InvEqP B". This may be the same as the condition 2015223017Sdim // tested in the max/min; if so, we can just return that. 2016223017Sdim if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B)) 2017223017Sdim return V; 2018223017Sdim if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B)) 2019223017Sdim return V; 2020223017Sdim // Otherwise, see if "A InvEqP B" simplifies. 2021223017Sdim if (MaxRecurse) 2022223017Sdim if (Value *V = SimplifyICmpInst(InvEqP, A, B, TD, DT, MaxRecurse-1)) 2023223017Sdim return V; 2024223017Sdim break; 2025223017Sdim } 2026223017Sdim case CmpInst::ICMP_UGE: 2027223017Sdim // Always true. 2028223017Sdim return Constant::getAllOnesValue(ITy); 2029223017Sdim case CmpInst::ICMP_ULT: 2030223017Sdim // Always false. 2031223017Sdim return Constant::getNullValue(ITy); 2032223017Sdim } 2033223017Sdim } 2034223017Sdim 2035223017Sdim // Variants on "max(x,y) >= min(x,z)". 2036223017Sdim Value *C, *D; 2037223017Sdim if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && 2038223017Sdim match(RHS, m_SMin(m_Value(C), m_Value(D))) && 2039223017Sdim (A == C || A == D || B == C || B == D)) { 2040223017Sdim // max(x, ?) pred min(x, ?). 2041223017Sdim if (Pred == CmpInst::ICMP_SGE) 2042223017Sdim // Always true. 2043223017Sdim return Constant::getAllOnesValue(ITy); 2044223017Sdim if (Pred == CmpInst::ICMP_SLT) 2045223017Sdim // Always false. 2046223017Sdim return Constant::getNullValue(ITy); 2047223017Sdim } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && 2048223017Sdim match(RHS, m_SMax(m_Value(C), m_Value(D))) && 2049223017Sdim (A == C || A == D || B == C || B == D)) { 2050223017Sdim // min(x, ?) pred max(x, ?). 2051223017Sdim if (Pred == CmpInst::ICMP_SLE) 2052223017Sdim // Always true. 2053223017Sdim return Constant::getAllOnesValue(ITy); 2054223017Sdim if (Pred == CmpInst::ICMP_SGT) 2055223017Sdim // Always false. 2056223017Sdim return Constant::getNullValue(ITy); 2057223017Sdim } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && 2058223017Sdim match(RHS, m_UMin(m_Value(C), m_Value(D))) && 2059223017Sdim (A == C || A == D || B == C || B == D)) { 2060223017Sdim // max(x, ?) pred min(x, ?). 2061223017Sdim if (Pred == CmpInst::ICMP_UGE) 2062223017Sdim // Always true. 2063223017Sdim return Constant::getAllOnesValue(ITy); 2064223017Sdim if (Pred == CmpInst::ICMP_ULT) 2065223017Sdim // Always false. 2066223017Sdim return Constant::getNullValue(ITy); 2067223017Sdim } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && 2068223017Sdim match(RHS, m_UMax(m_Value(C), m_Value(D))) && 2069223017Sdim (A == C || A == D || B == C || B == D)) { 2070223017Sdim // min(x, ?) pred max(x, ?). 2071223017Sdim if (Pred == CmpInst::ICMP_ULE) 2072223017Sdim // Always true. 2073223017Sdim return Constant::getAllOnesValue(ITy); 2074223017Sdim if (Pred == CmpInst::ICMP_UGT) 2075223017Sdim // Always false. 2076223017Sdim return Constant::getNullValue(ITy); 2077223017Sdim } 2078223017Sdim 2079218893Sdim // If the comparison is with the result of a select instruction, check whether 2080218893Sdim // comparing with either branch of the select always yields the same value. 2081218893Sdim if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) 2082218893Sdim if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, TD, DT, MaxRecurse)) 2083218893Sdim return V; 2084218893Sdim 2085218893Sdim // If the comparison is with the result of a phi instruction, check whether 2086218893Sdim // doing the compare with each incoming phi value yields a common result. 2087218893Sdim if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) 2088218893Sdim if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, TD, DT, MaxRecurse)) 2089218893Sdim return V; 2090218893Sdim 2091199481Srdivacky return 0; 2092199481Srdivacky} 2093199481Srdivacky 2094218893SdimValue *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 2095218893Sdim const TargetData *TD, const DominatorTree *DT) { 2096218893Sdim return ::SimplifyICmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit); 2097218893Sdim} 2098218893Sdim 2099199481Srdivacky/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can 2100199481Srdivacky/// fold the result. If not, this returns null. 2101218893Sdimstatic Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 2102218893Sdim const TargetData *TD, const DominatorTree *DT, 2103218893Sdim unsigned MaxRecurse) { 2104199481Srdivacky CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; 2105199481Srdivacky assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!"); 2106199481Srdivacky 2107199481Srdivacky if (Constant *CLHS = dyn_cast<Constant>(LHS)) { 2108199481Srdivacky if (Constant *CRHS = dyn_cast<Constant>(RHS)) 2109199481Srdivacky return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD); 2110218893Sdim 2111199481Srdivacky // If we have a constant, make sure it is on the RHS. 2112199481Srdivacky std::swap(LHS, RHS); 2113199481Srdivacky Pred = CmpInst::getSwappedPredicate(Pred); 2114199481Srdivacky } 2115218893Sdim 2116199481Srdivacky // Fold trivial predicates. 2117199481Srdivacky if (Pred == FCmpInst::FCMP_FALSE) 2118199481Srdivacky return ConstantInt::get(GetCompareTy(LHS), 0); 2119199481Srdivacky if (Pred == FCmpInst::FCMP_TRUE) 2120199481Srdivacky return ConstantInt::get(GetCompareTy(LHS), 1); 2121199481Srdivacky 2122199481Srdivacky if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef 2123199481Srdivacky return UndefValue::get(GetCompareTy(LHS)); 2124199481Srdivacky 2125199481Srdivacky // fcmp x,x -> true/false. Not all compares are foldable. 2126199481Srdivacky if (LHS == RHS) { 2127199481Srdivacky if (CmpInst::isTrueWhenEqual(Pred)) 2128199481Srdivacky return ConstantInt::get(GetCompareTy(LHS), 1); 2129199481Srdivacky if (CmpInst::isFalseWhenEqual(Pred)) 2130199481Srdivacky return ConstantInt::get(GetCompareTy(LHS), 0); 2131199481Srdivacky } 2132218893Sdim 2133199481Srdivacky // Handle fcmp with constant RHS 2134199481Srdivacky if (Constant *RHSC = dyn_cast<Constant>(RHS)) { 2135199481Srdivacky // If the constant is a nan, see if we can fold the comparison based on it. 2136199481Srdivacky if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) { 2137199481Srdivacky if (CFP->getValueAPF().isNaN()) { 2138199481Srdivacky if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo" 2139199481Srdivacky return ConstantInt::getFalse(CFP->getContext()); 2140199481Srdivacky assert(FCmpInst::isUnordered(Pred) && 2141199481Srdivacky "Comparison must be either ordered or unordered!"); 2142199481Srdivacky // True if unordered. 2143199481Srdivacky return ConstantInt::getTrue(CFP->getContext()); 2144199481Srdivacky } 2145204642Srdivacky // Check whether the constant is an infinity. 2146204642Srdivacky if (CFP->getValueAPF().isInfinity()) { 2147204642Srdivacky if (CFP->getValueAPF().isNegative()) { 2148204642Srdivacky switch (Pred) { 2149204642Srdivacky case FCmpInst::FCMP_OLT: 2150204642Srdivacky // No value is ordered and less than negative infinity. 2151204642Srdivacky return ConstantInt::getFalse(CFP->getContext()); 2152204642Srdivacky case FCmpInst::FCMP_UGE: 2153204642Srdivacky // All values are unordered with or at least negative infinity. 2154204642Srdivacky return ConstantInt::getTrue(CFP->getContext()); 2155204642Srdivacky default: 2156204642Srdivacky break; 2157204642Srdivacky } 2158204642Srdivacky } else { 2159204642Srdivacky switch (Pred) { 2160204642Srdivacky case FCmpInst::FCMP_OGT: 2161204642Srdivacky // No value is ordered and greater than infinity. 2162204642Srdivacky return ConstantInt::getFalse(CFP->getContext()); 2163204642Srdivacky case FCmpInst::FCMP_ULE: 2164204642Srdivacky // All values are unordered with and at most infinity. 2165204642Srdivacky return ConstantInt::getTrue(CFP->getContext()); 2166204642Srdivacky default: 2167204642Srdivacky break; 2168204642Srdivacky } 2169204642Srdivacky } 2170204642Srdivacky } 2171199481Srdivacky } 2172199481Srdivacky } 2173218893Sdim 2174218893Sdim // If the comparison is with the result of a select instruction, check whether 2175218893Sdim // comparing with either branch of the select always yields the same value. 2176218893Sdim if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) 2177218893Sdim if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, TD, DT, MaxRecurse)) 2178218893Sdim return V; 2179218893Sdim 2180218893Sdim // If the comparison is with the result of a phi instruction, check whether 2181218893Sdim // doing the compare with each incoming phi value yields a common result. 2182218893Sdim if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) 2183218893Sdim if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, TD, DT, MaxRecurse)) 2184218893Sdim return V; 2185218893Sdim 2186199481Srdivacky return 0; 2187199481Srdivacky} 2188199481Srdivacky 2189218893SdimValue *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 2190218893Sdim const TargetData *TD, const DominatorTree *DT) { 2191218893Sdim return ::SimplifyFCmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit); 2192218893Sdim} 2193218893Sdim 2194207618Srdivacky/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold 2195207618Srdivacky/// the result. If not, this returns null. 2196207618SrdivackyValue *llvm::SimplifySelectInst(Value *CondVal, Value *TrueVal, Value *FalseVal, 2197218893Sdim const TargetData *TD, const DominatorTree *) { 2198207618Srdivacky // select true, X, Y -> X 2199207618Srdivacky // select false, X, Y -> Y 2200207618Srdivacky if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal)) 2201207618Srdivacky return CB->getZExtValue() ? TrueVal : FalseVal; 2202218893Sdim 2203207618Srdivacky // select C, X, X -> X 2204207618Srdivacky if (TrueVal == FalseVal) 2205207618Srdivacky return TrueVal; 2206218893Sdim 2207207618Srdivacky if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X 2208207618Srdivacky return FalseVal; 2209207618Srdivacky if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X 2210207618Srdivacky return TrueVal; 2211207618Srdivacky if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y 2212207618Srdivacky if (isa<Constant>(TrueVal)) 2213207618Srdivacky return TrueVal; 2214207618Srdivacky return FalseVal; 2215207618Srdivacky } 2216218893Sdim 2217207618Srdivacky return 0; 2218207618Srdivacky} 2219207618Srdivacky 2220199989Srdivacky/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can 2221199989Srdivacky/// fold the result. If not, this returns null. 2222199989SrdivackyValue *llvm::SimplifyGEPInst(Value *const *Ops, unsigned NumOps, 2223218893Sdim const TargetData *TD, const DominatorTree *) { 2224218893Sdim // The type of the GEP pointer operand. 2225218893Sdim const PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()); 2226218893Sdim 2227199989Srdivacky // getelementptr P -> P. 2228199989Srdivacky if (NumOps == 1) 2229199989Srdivacky return Ops[0]; 2230199989Srdivacky 2231218893Sdim if (isa<UndefValue>(Ops[0])) { 2232218893Sdim // Compute the (pointer) type returned by the GEP instruction. 2233218893Sdim const Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, &Ops[1], 2234218893Sdim NumOps-1); 2235218893Sdim const Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace()); 2236218893Sdim return UndefValue::get(GEPTy); 2237218893Sdim } 2238199989Srdivacky 2239218893Sdim if (NumOps == 2) { 2240218893Sdim // getelementptr P, 0 -> P. 2241199989Srdivacky if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1])) 2242199989Srdivacky if (C->isZero()) 2243199989Srdivacky return Ops[0]; 2244218893Sdim // getelementptr P, N -> P if P points to a type of zero size. 2245218893Sdim if (TD) { 2246218893Sdim const Type *Ty = PtrTy->getElementType(); 2247218893Sdim if (Ty->isSized() && TD->getTypeAllocSize(Ty) == 0) 2248218893Sdim return Ops[0]; 2249218893Sdim } 2250218893Sdim } 2251218893Sdim 2252199989Srdivacky // Check to see if this is constant foldable. 2253199989Srdivacky for (unsigned i = 0; i != NumOps; ++i) 2254199989Srdivacky if (!isa<Constant>(Ops[i])) 2255199989Srdivacky return 0; 2256218893Sdim 2257199989Srdivacky return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), 2258199989Srdivacky (Constant *const*)Ops+1, NumOps-1); 2259199989Srdivacky} 2260199989Srdivacky 2261218893Sdim/// SimplifyPHINode - See if we can fold the given phi. If not, returns null. 2262218893Sdimstatic Value *SimplifyPHINode(PHINode *PN, const DominatorTree *DT) { 2263218893Sdim // If all of the PHI's incoming values are the same then replace the PHI node 2264218893Sdim // with the common value. 2265218893Sdim Value *CommonValue = 0; 2266218893Sdim bool HasUndefInput = false; 2267218893Sdim for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { 2268218893Sdim Value *Incoming = PN->getIncomingValue(i); 2269218893Sdim // If the incoming value is the phi node itself, it can safely be skipped. 2270218893Sdim if (Incoming == PN) continue; 2271218893Sdim if (isa<UndefValue>(Incoming)) { 2272218893Sdim // Remember that we saw an undef value, but otherwise ignore them. 2273218893Sdim HasUndefInput = true; 2274218893Sdim continue; 2275218893Sdim } 2276218893Sdim if (CommonValue && Incoming != CommonValue) 2277218893Sdim return 0; // Not the same, bail out. 2278218893Sdim CommonValue = Incoming; 2279218893Sdim } 2280199989Srdivacky 2281218893Sdim // If CommonValue is null then all of the incoming values were either undef or 2282218893Sdim // equal to the phi node itself. 2283218893Sdim if (!CommonValue) 2284218893Sdim return UndefValue::get(PN->getType()); 2285218893Sdim 2286218893Sdim // If we have a PHI node like phi(X, undef, X), where X is defined by some 2287218893Sdim // instruction, we cannot return X as the result of the PHI node unless it 2288218893Sdim // dominates the PHI block. 2289218893Sdim if (HasUndefInput) 2290218893Sdim return ValueDominatesPHI(CommonValue, PN, DT) ? CommonValue : 0; 2291218893Sdim 2292218893Sdim return CommonValue; 2293218893Sdim} 2294218893Sdim 2295218893Sdim 2296199481Srdivacky//=== Helper functions for higher up the class hierarchy. 2297199481Srdivacky 2298199481Srdivacky/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can 2299199481Srdivacky/// fold the result. If not, this returns null. 2300218893Sdimstatic Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 2301218893Sdim const TargetData *TD, const DominatorTree *DT, 2302218893Sdim unsigned MaxRecurse) { 2303199481Srdivacky switch (Opcode) { 2304218893Sdim case Instruction::Add: 2305218893Sdim return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false, 2306218893Sdim TD, DT, MaxRecurse); 2307218893Sdim case Instruction::Sub: 2308218893Sdim return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false, 2309218893Sdim TD, DT, MaxRecurse); 2310218893Sdim case Instruction::Mul: return SimplifyMulInst (LHS, RHS, TD, DT, MaxRecurse); 2311218893Sdim case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, TD, DT, MaxRecurse); 2312218893Sdim case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, TD, DT, MaxRecurse); 2313218893Sdim case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, TD, DT, MaxRecurse); 2314221345Sdim case Instruction::SRem: return SimplifySRemInst(LHS, RHS, TD, DT, MaxRecurse); 2315221345Sdim case Instruction::URem: return SimplifyURemInst(LHS, RHS, TD, DT, MaxRecurse); 2316221345Sdim case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, TD, DT, MaxRecurse); 2317218893Sdim case Instruction::Shl: 2318218893Sdim return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false, 2319218893Sdim TD, DT, MaxRecurse); 2320218893Sdim case Instruction::LShr: 2321218893Sdim return SimplifyLShrInst(LHS, RHS, /*isExact*/false, TD, DT, MaxRecurse); 2322218893Sdim case Instruction::AShr: 2323218893Sdim return SimplifyAShrInst(LHS, RHS, /*isExact*/false, TD, DT, MaxRecurse); 2324218893Sdim case Instruction::And: return SimplifyAndInst(LHS, RHS, TD, DT, MaxRecurse); 2325218893Sdim case Instruction::Or: return SimplifyOrInst (LHS, RHS, TD, DT, MaxRecurse); 2326218893Sdim case Instruction::Xor: return SimplifyXorInst(LHS, RHS, TD, DT, MaxRecurse); 2327199481Srdivacky default: 2328199481Srdivacky if (Constant *CLHS = dyn_cast<Constant>(LHS)) 2329199481Srdivacky if (Constant *CRHS = dyn_cast<Constant>(RHS)) { 2330199481Srdivacky Constant *COps[] = {CLHS, CRHS}; 2331199481Srdivacky return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, 2, TD); 2332199481Srdivacky } 2333218893Sdim 2334218893Sdim // If the operation is associative, try some generic simplifications. 2335218893Sdim if (Instruction::isAssociative(Opcode)) 2336218893Sdim if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, TD, DT, 2337218893Sdim MaxRecurse)) 2338218893Sdim return V; 2339218893Sdim 2340218893Sdim // If the operation is with the result of a select instruction, check whether 2341218893Sdim // operating on either branch of the select always yields the same value. 2342218893Sdim if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) 2343218893Sdim if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, TD, DT, 2344218893Sdim MaxRecurse)) 2345218893Sdim return V; 2346218893Sdim 2347218893Sdim // If the operation is with the result of a phi instruction, check whether 2348218893Sdim // operating on all incoming values of the phi always yields the same value. 2349218893Sdim if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) 2350218893Sdim if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, TD, DT, MaxRecurse)) 2351218893Sdim return V; 2352218893Sdim 2353199481Srdivacky return 0; 2354199481Srdivacky } 2355199481Srdivacky} 2356199481Srdivacky 2357218893SdimValue *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 2358218893Sdim const TargetData *TD, const DominatorTree *DT) { 2359218893Sdim return ::SimplifyBinOp(Opcode, LHS, RHS, TD, DT, RecursionLimit); 2360218893Sdim} 2361218893Sdim 2362199481Srdivacky/// SimplifyCmpInst - Given operands for a CmpInst, see if we can 2363199481Srdivacky/// fold the result. 2364218893Sdimstatic Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 2365218893Sdim const TargetData *TD, const DominatorTree *DT, 2366218893Sdim unsigned MaxRecurse) { 2367199481Srdivacky if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate)) 2368218893Sdim return SimplifyICmpInst(Predicate, LHS, RHS, TD, DT, MaxRecurse); 2369218893Sdim return SimplifyFCmpInst(Predicate, LHS, RHS, TD, DT, MaxRecurse); 2370199481Srdivacky} 2371199481Srdivacky 2372218893SdimValue *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 2373218893Sdim const TargetData *TD, const DominatorTree *DT) { 2374218893Sdim return ::SimplifyCmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit); 2375218893Sdim} 2376199481Srdivacky 2377199481Srdivacky/// SimplifyInstruction - See if we can compute a simplified version of this 2378199481Srdivacky/// instruction. If not, this returns null. 2379218893SdimValue *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD, 2380218893Sdim const DominatorTree *DT) { 2381218893Sdim Value *Result; 2382218893Sdim 2383199481Srdivacky switch (I->getOpcode()) { 2384199481Srdivacky default: 2385218893Sdim Result = ConstantFoldInstruction(I, TD); 2386218893Sdim break; 2387199989Srdivacky case Instruction::Add: 2388218893Sdim Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1), 2389218893Sdim cast<BinaryOperator>(I)->hasNoSignedWrap(), 2390218893Sdim cast<BinaryOperator>(I)->hasNoUnsignedWrap(), 2391218893Sdim TD, DT); 2392218893Sdim break; 2393218893Sdim case Instruction::Sub: 2394218893Sdim Result = SimplifySubInst(I->getOperand(0), I->getOperand(1), 2395218893Sdim cast<BinaryOperator>(I)->hasNoSignedWrap(), 2396218893Sdim cast<BinaryOperator>(I)->hasNoUnsignedWrap(), 2397218893Sdim TD, DT); 2398218893Sdim break; 2399218893Sdim case Instruction::Mul: 2400218893Sdim Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, DT); 2401218893Sdim break; 2402218893Sdim case Instruction::SDiv: 2403218893Sdim Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, DT); 2404218893Sdim break; 2405218893Sdim case Instruction::UDiv: 2406218893Sdim Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, DT); 2407218893Sdim break; 2408218893Sdim case Instruction::FDiv: 2409218893Sdim Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, DT); 2410218893Sdim break; 2411221345Sdim case Instruction::SRem: 2412221345Sdim Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, DT); 2413221345Sdim break; 2414221345Sdim case Instruction::URem: 2415221345Sdim Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, DT); 2416221345Sdim break; 2417221345Sdim case Instruction::FRem: 2418221345Sdim Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, DT); 2419221345Sdim break; 2420218893Sdim case Instruction::Shl: 2421218893Sdim Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1), 2422218893Sdim cast<BinaryOperator>(I)->hasNoSignedWrap(), 2423218893Sdim cast<BinaryOperator>(I)->hasNoUnsignedWrap(), 2424218893Sdim TD, DT); 2425218893Sdim break; 2426218893Sdim case Instruction::LShr: 2427218893Sdim Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1), 2428218893Sdim cast<BinaryOperator>(I)->isExact(), 2429218893Sdim TD, DT); 2430218893Sdim break; 2431218893Sdim case Instruction::AShr: 2432218893Sdim Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1), 2433218893Sdim cast<BinaryOperator>(I)->isExact(), 2434218893Sdim TD, DT); 2435218893Sdim break; 2436199481Srdivacky case Instruction::And: 2437218893Sdim Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, DT); 2438218893Sdim break; 2439199481Srdivacky case Instruction::Or: 2440218893Sdim Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, DT); 2441218893Sdim break; 2442218893Sdim case Instruction::Xor: 2443218893Sdim Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, DT); 2444218893Sdim break; 2445199481Srdivacky case Instruction::ICmp: 2446218893Sdim Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(), 2447218893Sdim I->getOperand(0), I->getOperand(1), TD, DT); 2448218893Sdim break; 2449199481Srdivacky case Instruction::FCmp: 2450218893Sdim Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), 2451218893Sdim I->getOperand(0), I->getOperand(1), TD, DT); 2452218893Sdim break; 2453207618Srdivacky case Instruction::Select: 2454218893Sdim Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1), 2455218893Sdim I->getOperand(2), TD, DT); 2456218893Sdim break; 2457199989Srdivacky case Instruction::GetElementPtr: { 2458199989Srdivacky SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end()); 2459218893Sdim Result = SimplifyGEPInst(&Ops[0], Ops.size(), TD, DT); 2460218893Sdim break; 2461199481Srdivacky } 2462218893Sdim case Instruction::PHI: 2463218893Sdim Result = SimplifyPHINode(cast<PHINode>(I), DT); 2464218893Sdim break; 2465199989Srdivacky } 2466218893Sdim 2467218893Sdim /// If called on unreachable code, the above logic may report that the 2468218893Sdim /// instruction simplified to itself. Make life easier for users by 2469218893Sdim /// detecting that case here, returning a safe value instead. 2470218893Sdim return Result == I ? UndefValue::get(I->getType()) : Result; 2471199481Srdivacky} 2472199481Srdivacky 2473199481Srdivacky/// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then 2474199481Srdivacky/// delete the From instruction. In addition to a basic RAUW, this does a 2475199481Srdivacky/// recursive simplification of the newly formed instructions. This catches 2476199481Srdivacky/// things where one simplification exposes other opportunities. This only 2477199481Srdivacky/// simplifies and deletes scalar operations, it does not change the CFG. 2478199481Srdivacky/// 2479199481Srdivackyvoid llvm::ReplaceAndSimplifyAllUses(Instruction *From, Value *To, 2480218893Sdim const TargetData *TD, 2481218893Sdim const DominatorTree *DT) { 2482199481Srdivacky assert(From != To && "ReplaceAndSimplifyAllUses(X,X) is not valid!"); 2483218893Sdim 2484210299Sed // FromHandle/ToHandle - This keeps a WeakVH on the from/to values so that 2485210299Sed // we can know if it gets deleted out from under us or replaced in a 2486210299Sed // recursive simplification. 2487199481Srdivacky WeakVH FromHandle(From); 2488210299Sed WeakVH ToHandle(To); 2489218893Sdim 2490199481Srdivacky while (!From->use_empty()) { 2491199481Srdivacky // Update the instruction to use the new value. 2492210299Sed Use &TheUse = From->use_begin().getUse(); 2493210299Sed Instruction *User = cast<Instruction>(TheUse.getUser()); 2494210299Sed TheUse = To; 2495210299Sed 2496210299Sed // Check to see if the instruction can be folded due to the operand 2497210299Sed // replacement. For example changing (or X, Y) into (or X, -1) can replace 2498210299Sed // the 'or' with -1. 2499210299Sed Value *SimplifiedVal; 2500210299Sed { 2501210299Sed // Sanity check to make sure 'User' doesn't dangle across 2502210299Sed // SimplifyInstruction. 2503210299Sed AssertingVH<> UserHandle(User); 2504218893Sdim 2505218893Sdim SimplifiedVal = SimplifyInstruction(User, TD, DT); 2506210299Sed if (SimplifiedVal == 0) continue; 2507210299Sed } 2508218893Sdim 2509210299Sed // Recursively simplify this user to the new value. 2510218893Sdim ReplaceAndSimplifyAllUses(User, SimplifiedVal, TD, DT); 2511210299Sed From = dyn_cast_or_null<Instruction>((Value*)FromHandle); 2512210299Sed To = ToHandle; 2513218893Sdim 2514210299Sed assert(ToHandle && "To value deleted by recursive simplification?"); 2515218893Sdim 2516210299Sed // If the recursive simplification ended up revisiting and deleting 2517210299Sed // 'From' then we're done. 2518210299Sed if (From == 0) 2519210299Sed return; 2520199481Srdivacky } 2521218893Sdim 2522210299Sed // If 'From' has value handles referring to it, do a real RAUW to update them. 2523210299Sed From->replaceAllUsesWith(To); 2524218893Sdim 2525199481Srdivacky From->eraseFromParent(); 2526199481Srdivacky} 2527