1//===- IVUsers.cpp - Induction Variable Users -------------------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements bookkeeping for "interesting" users of expressions
11// computed from induction variables.
12//
13//===----------------------------------------------------------------------===//
14
15#define DEBUG_TYPE "iv-users"
16#include "llvm/Analysis/IVUsers.h"
17#include "llvm/Constants.h"
18#include "llvm/Instructions.h"
19#include "llvm/Type.h"
20#include "llvm/DerivedTypes.h"
21#include "llvm/Analysis/Dominators.h"
22#include "llvm/Analysis/LoopPass.h"
23#include "llvm/Analysis/ScalarEvolutionExpressions.h"
24#include "llvm/ADT/STLExtras.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/raw_ostream.h"
27#include <algorithm>
28using namespace llvm;
29
30char IVUsers::ID = 0;
31static RegisterPass<IVUsers>
32X("iv-users", "Induction Variable Users", false, true);
33
34Pass *llvm::createIVUsersPass() {
35 return new IVUsers();
36}
37
38/// containsAddRecFromDifferentLoop - Determine whether expression S involves a
39/// subexpression that is an AddRec from a loop other than L. An outer loop
40/// of L is OK, but not an inner loop nor a disjoint loop.
41static bool containsAddRecFromDifferentLoop(const SCEV *S, Loop *L) {
42 // This is very common, put it first.
43 if (isa<SCEVConstant>(S))
44 return false;
45 if (const SCEVCommutativeExpr *AE = dyn_cast<SCEVCommutativeExpr>(S)) {
46 for (unsigned int i=0; i< AE->getNumOperands(); i++)
47 if (containsAddRecFromDifferentLoop(AE->getOperand(i), L))
48 return true;
49 return false;
50 }
51 if (const SCEVAddRecExpr *AE = dyn_cast<SCEVAddRecExpr>(S)) {
52 if (const Loop *newLoop = AE->getLoop()) {
53 if (newLoop == L)
54 return false;
55 // if newLoop is an outer loop of L, this is OK.
| 1//===- IVUsers.cpp - Induction Variable Users -------------------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements bookkeeping for "interesting" users of expressions
11// computed from induction variables.
12//
13//===----------------------------------------------------------------------===//
14
15#define DEBUG_TYPE "iv-users"
16#include "llvm/Analysis/IVUsers.h"
17#include "llvm/Constants.h"
18#include "llvm/Instructions.h"
19#include "llvm/Type.h"
20#include "llvm/DerivedTypes.h"
21#include "llvm/Analysis/Dominators.h"
22#include "llvm/Analysis/LoopPass.h"
23#include "llvm/Analysis/ScalarEvolutionExpressions.h"
24#include "llvm/ADT/STLExtras.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/raw_ostream.h"
27#include <algorithm>
28using namespace llvm;
29
30char IVUsers::ID = 0;
31static RegisterPass<IVUsers>
32X("iv-users", "Induction Variable Users", false, true);
33
34Pass *llvm::createIVUsersPass() {
35 return new IVUsers();
36}
37
38/// containsAddRecFromDifferentLoop - Determine whether expression S involves a
39/// subexpression that is an AddRec from a loop other than L. An outer loop
40/// of L is OK, but not an inner loop nor a disjoint loop.
41static bool containsAddRecFromDifferentLoop(const SCEV *S, Loop *L) {
42 // This is very common, put it first.
43 if (isa<SCEVConstant>(S))
44 return false;
45 if (const SCEVCommutativeExpr *AE = dyn_cast<SCEVCommutativeExpr>(S)) {
46 for (unsigned int i=0; i< AE->getNumOperands(); i++)
47 if (containsAddRecFromDifferentLoop(AE->getOperand(i), L))
48 return true;
49 return false;
50 }
51 if (const SCEVAddRecExpr *AE = dyn_cast<SCEVAddRecExpr>(S)) {
52 if (const Loop *newLoop = AE->getLoop()) {
53 if (newLoop == L)
54 return false;
55 // if newLoop is an outer loop of L, this is OK.
|
56 if (newLoop->contains(L->getHeader()))
| 56 if (newLoop->contains(L))
|
57 return false;
58 }
59 return true;
60 }
61 if (const SCEVUDivExpr *DE = dyn_cast<SCEVUDivExpr>(S))
62 return containsAddRecFromDifferentLoop(DE->getLHS(), L) ||
63 containsAddRecFromDifferentLoop(DE->getRHS(), L);
64#if 0
65 // SCEVSDivExpr has been backed out temporarily, but will be back; we'll
66 // need this when it is.
67 if (const SCEVSDivExpr *DE = dyn_cast<SCEVSDivExpr>(S))
68 return containsAddRecFromDifferentLoop(DE->getLHS(), L) ||
69 containsAddRecFromDifferentLoop(DE->getRHS(), L);
70#endif
71 if (const SCEVCastExpr *CE = dyn_cast<SCEVCastExpr>(S))
72 return containsAddRecFromDifferentLoop(CE->getOperand(), L);
73 return false;
74}
75
76/// getSCEVStartAndStride - Compute the start and stride of this expression,
77/// returning false if the expression is not a start/stride pair, or true if it
78/// is. The stride must be a loop invariant expression, but the start may be
79/// a mix of loop invariant and loop variant expressions. The start cannot,
80/// however, contain an AddRec from a different loop, unless that loop is an
81/// outer loop of the current loop.
82static bool getSCEVStartAndStride(const SCEV *&SH, Loop *L, Loop *UseLoop,
83 const SCEV *&Start, const SCEV *&Stride,
84 ScalarEvolution *SE, DominatorTree *DT) {
85 const SCEV *TheAddRec = Start; // Initialize to zero.
86
87 // If the outer level is an AddExpr, the operands are all start values except
88 // for a nested AddRecExpr.
89 if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(SH)) {
90 for (unsigned i = 0, e = AE->getNumOperands(); i != e; ++i)
91 if (const SCEVAddRecExpr *AddRec =
92 dyn_cast<SCEVAddRecExpr>(AE->getOperand(i))) {
93 if (AddRec->getLoop() == L)
94 TheAddRec = SE->getAddExpr(AddRec, TheAddRec);
95 else
96 return false; // Nested IV of some sort?
97 } else {
98 Start = SE->getAddExpr(Start, AE->getOperand(i));
99 }
100 } else if (isa<SCEVAddRecExpr>(SH)) {
101 TheAddRec = SH;
102 } else {
103 return false; // not analyzable.
104 }
105
106 const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(TheAddRec);
107 if (!AddRec || AddRec->getLoop() != L) return false;
108
109 // Use getSCEVAtScope to attempt to simplify other loops out of
110 // the picture.
111 const SCEV *AddRecStart = AddRec->getStart();
112 AddRecStart = SE->getSCEVAtScope(AddRecStart, UseLoop);
113 const SCEV *AddRecStride = AddRec->getStepRecurrence(*SE);
114
115 // FIXME: If Start contains an SCEVAddRecExpr from a different loop, other
116 // than an outer loop of the current loop, reject it. LSR has no concept of
117 // operating on more than one loop at a time so don't confuse it with such
118 // expressions.
119 if (containsAddRecFromDifferentLoop(AddRecStart, L))
120 return false;
121
122 Start = SE->getAddExpr(Start, AddRecStart);
123
124 // If stride is an instruction, make sure it properly dominates the header.
125 // Otherwise we could end up with a use before def situation.
126 if (!isa<SCEVConstant>(AddRecStride)) {
127 BasicBlock *Header = L->getHeader();
128 if (!AddRecStride->properlyDominates(Header, DT))
129 return false;
130
| 57 return false;
58 }
59 return true;
60 }
61 if (const SCEVUDivExpr *DE = dyn_cast<SCEVUDivExpr>(S))
62 return containsAddRecFromDifferentLoop(DE->getLHS(), L) ||
63 containsAddRecFromDifferentLoop(DE->getRHS(), L);
64#if 0
65 // SCEVSDivExpr has been backed out temporarily, but will be back; we'll
66 // need this when it is.
67 if (const SCEVSDivExpr *DE = dyn_cast<SCEVSDivExpr>(S))
68 return containsAddRecFromDifferentLoop(DE->getLHS(), L) ||
69 containsAddRecFromDifferentLoop(DE->getRHS(), L);
70#endif
71 if (const SCEVCastExpr *CE = dyn_cast<SCEVCastExpr>(S))
72 return containsAddRecFromDifferentLoop(CE->getOperand(), L);
73 return false;
74}
75
76/// getSCEVStartAndStride - Compute the start and stride of this expression,
77/// returning false if the expression is not a start/stride pair, or true if it
78/// is. The stride must be a loop invariant expression, but the start may be
79/// a mix of loop invariant and loop variant expressions. The start cannot,
80/// however, contain an AddRec from a different loop, unless that loop is an
81/// outer loop of the current loop.
82static bool getSCEVStartAndStride(const SCEV *&SH, Loop *L, Loop *UseLoop,
83 const SCEV *&Start, const SCEV *&Stride,
84 ScalarEvolution *SE, DominatorTree *DT) {
85 const SCEV *TheAddRec = Start; // Initialize to zero.
86
87 // If the outer level is an AddExpr, the operands are all start values except
88 // for a nested AddRecExpr.
89 if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(SH)) {
90 for (unsigned i = 0, e = AE->getNumOperands(); i != e; ++i)
91 if (const SCEVAddRecExpr *AddRec =
92 dyn_cast<SCEVAddRecExpr>(AE->getOperand(i))) {
93 if (AddRec->getLoop() == L)
94 TheAddRec = SE->getAddExpr(AddRec, TheAddRec);
95 else
96 return false; // Nested IV of some sort?
97 } else {
98 Start = SE->getAddExpr(Start, AE->getOperand(i));
99 }
100 } else if (isa<SCEVAddRecExpr>(SH)) {
101 TheAddRec = SH;
102 } else {
103 return false; // not analyzable.
104 }
105
106 const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(TheAddRec);
107 if (!AddRec || AddRec->getLoop() != L) return false;
108
109 // Use getSCEVAtScope to attempt to simplify other loops out of
110 // the picture.
111 const SCEV *AddRecStart = AddRec->getStart();
112 AddRecStart = SE->getSCEVAtScope(AddRecStart, UseLoop);
113 const SCEV *AddRecStride = AddRec->getStepRecurrence(*SE);
114
115 // FIXME: If Start contains an SCEVAddRecExpr from a different loop, other
116 // than an outer loop of the current loop, reject it. LSR has no concept of
117 // operating on more than one loop at a time so don't confuse it with such
118 // expressions.
119 if (containsAddRecFromDifferentLoop(AddRecStart, L))
120 return false;
121
122 Start = SE->getAddExpr(Start, AddRecStart);
123
124 // If stride is an instruction, make sure it properly dominates the header.
125 // Otherwise we could end up with a use before def situation.
126 if (!isa<SCEVConstant>(AddRecStride)) {
127 BasicBlock *Header = L->getHeader();
128 if (!AddRecStride->properlyDominates(Header, DT))
129 return false;
130
|
131 DEBUG(errs() << "[" << L->getHeader()->getName()
| 131 DEBUG(dbgs() << "[" << L->getHeader()->getName()
|
132 << "] Variable stride: " << *AddRec << "\n");
133 }
134
135 Stride = AddRecStride;
136 return true;
137}
138
139/// IVUseShouldUsePostIncValue - We have discovered a "User" of an IV expression
140/// and now we need to decide whether the user should use the preinc or post-inc
141/// value. If this user should use the post-inc version of the IV, return true.
142///
143/// Choosing wrong here can break dominance properties (if we choose to use the
144/// post-inc value when we cannot) or it can end up adding extra live-ranges to
145/// the loop, resulting in reg-reg copies (if we use the pre-inc value when we
146/// should use the post-inc value).
147static bool IVUseShouldUsePostIncValue(Instruction *User, Instruction *IV,
148 Loop *L, LoopInfo *LI, DominatorTree *DT,
149 Pass *P) {
150 // If the user is in the loop, use the preinc value.
| 132 << "] Variable stride: " << *AddRec << "\n");
133 }
134
135 Stride = AddRecStride;
136 return true;
137}
138
139/// IVUseShouldUsePostIncValue - We have discovered a "User" of an IV expression
140/// and now we need to decide whether the user should use the preinc or post-inc
141/// value. If this user should use the post-inc version of the IV, return true.
142///
143/// Choosing wrong here can break dominance properties (if we choose to use the
144/// post-inc value when we cannot) or it can end up adding extra live-ranges to
145/// the loop, resulting in reg-reg copies (if we use the pre-inc value when we
146/// should use the post-inc value).
147static bool IVUseShouldUsePostIncValue(Instruction *User, Instruction *IV,
148 Loop *L, LoopInfo *LI, DominatorTree *DT,
149 Pass *P) {
150 // If the user is in the loop, use the preinc value.
|
151 if (L->contains(User->getParent())) return false;
| 151 if (L->contains(User)) return false;
|
152
153 BasicBlock *LatchBlock = L->getLoopLatch();
154 if (!LatchBlock)
155 return false;
156
157 // Ok, the user is outside of the loop. If it is dominated by the latch
158 // block, use the post-inc value.
159 if (DT->dominates(LatchBlock, User->getParent()))
160 return true;
161
162 // There is one case we have to be careful of: PHI nodes. These little guys
163 // can live in blocks that are not dominated by the latch block, but (since
164 // their uses occur in the predecessor block, not the block the PHI lives in)
165 // should still use the post-inc value. Check for this case now.
166 PHINode *PN = dyn_cast<PHINode>(User);
167 if (!PN) return false; // not a phi, not dominated by latch block.
168
169 // Look at all of the uses of IV by the PHI node. If any use corresponds to
170 // a block that is not dominated by the latch block, give up and use the
171 // preincremented value.
172 unsigned NumUses = 0;
173 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
174 if (PN->getIncomingValue(i) == IV) {
175 ++NumUses;
176 if (!DT->dominates(LatchBlock, PN->getIncomingBlock(i)))
177 return false;
178 }
179
180 // Okay, all uses of IV by PN are in predecessor blocks that really are
181 // dominated by the latch block. Use the post-incremented value.
182 return true;
183}
184
185/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
186/// reducible SCEV, recursively add its users to the IVUsesByStride set and
187/// return true. Otherwise, return false.
188bool IVUsers::AddUsersIfInteresting(Instruction *I) {
189 if (!SE->isSCEVable(I->getType()))
190 return false; // Void and FP expressions cannot be reduced.
191
192 // LSR is not APInt clean, do not touch integers bigger than 64-bits.
193 if (SE->getTypeSizeInBits(I->getType()) > 64)
194 return false;
195
196 if (!Processed.insert(I))
197 return true; // Instruction already handled.
198
199 // Get the symbolic expression for this instruction.
200 const SCEV *ISE = SE->getSCEV(I);
201 if (isa<SCEVCouldNotCompute>(ISE)) return false;
202
203 // Get the start and stride for this expression.
204 Loop *UseLoop = LI->getLoopFor(I->getParent());
205 const SCEV *Start = SE->getIntegerSCEV(0, ISE->getType());
206 const SCEV *Stride = Start;
207
208 if (!getSCEVStartAndStride(ISE, L, UseLoop, Start, Stride, SE, DT))
209 return false; // Non-reducible symbolic expression, bail out.
210
211 // Keep things simple. Don't touch loop-variant strides.
| 152
153 BasicBlock *LatchBlock = L->getLoopLatch();
154 if (!LatchBlock)
155 return false;
156
157 // Ok, the user is outside of the loop. If it is dominated by the latch
158 // block, use the post-inc value.
159 if (DT->dominates(LatchBlock, User->getParent()))
160 return true;
161
162 // There is one case we have to be careful of: PHI nodes. These little guys
163 // can live in blocks that are not dominated by the latch block, but (since
164 // their uses occur in the predecessor block, not the block the PHI lives in)
165 // should still use the post-inc value. Check for this case now.
166 PHINode *PN = dyn_cast<PHINode>(User);
167 if (!PN) return false; // not a phi, not dominated by latch block.
168
169 // Look at all of the uses of IV by the PHI node. If any use corresponds to
170 // a block that is not dominated by the latch block, give up and use the
171 // preincremented value.
172 unsigned NumUses = 0;
173 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
174 if (PN->getIncomingValue(i) == IV) {
175 ++NumUses;
176 if (!DT->dominates(LatchBlock, PN->getIncomingBlock(i)))
177 return false;
178 }
179
180 // Okay, all uses of IV by PN are in predecessor blocks that really are
181 // dominated by the latch block. Use the post-incremented value.
182 return true;
183}
184
185/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
186/// reducible SCEV, recursively add its users to the IVUsesByStride set and
187/// return true. Otherwise, return false.
188bool IVUsers::AddUsersIfInteresting(Instruction *I) {
189 if (!SE->isSCEVable(I->getType()))
190 return false; // Void and FP expressions cannot be reduced.
191
192 // LSR is not APInt clean, do not touch integers bigger than 64-bits.
193 if (SE->getTypeSizeInBits(I->getType()) > 64)
194 return false;
195
196 if (!Processed.insert(I))
197 return true; // Instruction already handled.
198
199 // Get the symbolic expression for this instruction.
200 const SCEV *ISE = SE->getSCEV(I);
201 if (isa<SCEVCouldNotCompute>(ISE)) return false;
202
203 // Get the start and stride for this expression.
204 Loop *UseLoop = LI->getLoopFor(I->getParent());
205 const SCEV *Start = SE->getIntegerSCEV(0, ISE->getType());
206 const SCEV *Stride = Start;
207
208 if (!getSCEVStartAndStride(ISE, L, UseLoop, Start, Stride, SE, DT))
209 return false; // Non-reducible symbolic expression, bail out.
210
211 // Keep things simple. Don't touch loop-variant strides.
|
212 if (!Stride->isLoopInvariant(L) && L->contains(I->getParent()))
| 212 if (!Stride->isLoopInvariant(L) && L->contains(I))
|
213 return false;
214
215 SmallPtrSet<Instruction *, 4> UniqueUsers;
216 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
217 UI != E; ++UI) {
218 Instruction *User = cast<Instruction>(*UI);
219 if (!UniqueUsers.insert(User))
220 continue;
221
222 // Do not infinitely recurse on PHI nodes.
223 if (isa<PHINode>(User) && Processed.count(User))
224 continue;
225
226 // Descend recursively, but not into PHI nodes outside the current loop.
227 // It's important to see the entire expression outside the loop to get
228 // choices that depend on addressing mode use right, although we won't
229 // consider references ouside the loop in all cases.
230 // If User is already in Processed, we don't want to recurse into it again,
231 // but do want to record a second reference in the same instruction.
232 bool AddUserToIVUsers = false;
233 if (LI->getLoopFor(User->getParent()) != L) {
234 if (isa<PHINode>(User) || Processed.count(User) ||
235 !AddUsersIfInteresting(User)) {
| 213 return false;
214
215 SmallPtrSet<Instruction *, 4> UniqueUsers;
216 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
217 UI != E; ++UI) {
218 Instruction *User = cast<Instruction>(*UI);
219 if (!UniqueUsers.insert(User))
220 continue;
221
222 // Do not infinitely recurse on PHI nodes.
223 if (isa<PHINode>(User) && Processed.count(User))
224 continue;
225
226 // Descend recursively, but not into PHI nodes outside the current loop.
227 // It's important to see the entire expression outside the loop to get
228 // choices that depend on addressing mode use right, although we won't
229 // consider references ouside the loop in all cases.
230 // If User is already in Processed, we don't want to recurse into it again,
231 // but do want to record a second reference in the same instruction.
232 bool AddUserToIVUsers = false;
233 if (LI->getLoopFor(User->getParent()) != L) {
234 if (isa<PHINode>(User) || Processed.count(User) ||
235 !AddUsersIfInteresting(User)) {
|
236 DEBUG(errs() << "FOUND USER in other loop: " << *User << '\n'
| 236 DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n'
|
237 << " OF SCEV: " << *ISE << '\n');
238 AddUserToIVUsers = true;
239 }
240 } else if (Processed.count(User) ||
241 !AddUsersIfInteresting(User)) {
| 237 << " OF SCEV: " << *ISE << '\n');
238 AddUserToIVUsers = true;
239 }
240 } else if (Processed.count(User) ||
241 !AddUsersIfInteresting(User)) {
|
242 DEBUG(errs() << "FOUND USER: " << *User << '\n'
| 242 DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
|
243 << " OF SCEV: " << *ISE << '\n');
244 AddUserToIVUsers = true;
245 }
246
247 if (AddUserToIVUsers) {
248 IVUsersOfOneStride *StrideUses = IVUsesByStride[Stride];
249 if (!StrideUses) { // First occurrence of this stride?
250 StrideOrder.push_back(Stride);
251 StrideUses = new IVUsersOfOneStride(Stride);
252 IVUses.push_back(StrideUses);
253 IVUsesByStride[Stride] = StrideUses;
254 }
255
256 // Okay, we found a user that we cannot reduce. Analyze the instruction
257 // and decide what to do with it. If we are a use inside of the loop, use
258 // the value before incrementation, otherwise use it after incrementation.
259 if (IVUseShouldUsePostIncValue(User, I, L, LI, DT, this)) {
260 // The value used will be incremented by the stride more than we are
261 // expecting, so subtract this off.
262 const SCEV *NewStart = SE->getMinusSCEV(Start, Stride);
263 StrideUses->addUser(NewStart, User, I);
264 StrideUses->Users.back().setIsUseOfPostIncrementedValue(true);
| 243 << " OF SCEV: " << *ISE << '\n');
244 AddUserToIVUsers = true;
245 }
246
247 if (AddUserToIVUsers) {
248 IVUsersOfOneStride *StrideUses = IVUsesByStride[Stride];
249 if (!StrideUses) { // First occurrence of this stride?
250 StrideOrder.push_back(Stride);
251 StrideUses = new IVUsersOfOneStride(Stride);
252 IVUses.push_back(StrideUses);
253 IVUsesByStride[Stride] = StrideUses;
254 }
255
256 // Okay, we found a user that we cannot reduce. Analyze the instruction
257 // and decide what to do with it. If we are a use inside of the loop, use
258 // the value before incrementation, otherwise use it after incrementation.
259 if (IVUseShouldUsePostIncValue(User, I, L, LI, DT, this)) {
260 // The value used will be incremented by the stride more than we are
261 // expecting, so subtract this off.
262 const SCEV *NewStart = SE->getMinusSCEV(Start, Stride);
263 StrideUses->addUser(NewStart, User, I);
264 StrideUses->Users.back().setIsUseOfPostIncrementedValue(true);
|
265 DEBUG(errs() << " USING POSTINC SCEV, START=" << *NewStart<< "\n");
| 265 DEBUG(dbgs() << " USING POSTINC SCEV, START=" << *NewStart<< "\n");
|
266 } else {
267 StrideUses->addUser(Start, User, I);
268 }
269 }
270 }
271 return true;
272}
273
274void IVUsers::AddUser(const SCEV *Stride, const SCEV *Offset,
275 Instruction *User, Value *Operand) {
276 IVUsersOfOneStride *StrideUses = IVUsesByStride[Stride];
277 if (!StrideUses) { // First occurrence of this stride?
278 StrideOrder.push_back(Stride);
279 StrideUses = new IVUsersOfOneStride(Stride);
280 IVUses.push_back(StrideUses);
281 IVUsesByStride[Stride] = StrideUses;
282 }
283 IVUsesByStride[Stride]->addUser(Offset, User, Operand);
284}
285
286IVUsers::IVUsers()
287 : LoopPass(&ID) {
288}
289
290void IVUsers::getAnalysisUsage(AnalysisUsage &AU) const {
291 AU.addRequired<LoopInfo>();
292 AU.addRequired<DominatorTree>();
293 AU.addRequired<ScalarEvolution>();
294 AU.setPreservesAll();
295}
296
297bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) {
298
299 L = l;
300 LI = &getAnalysis<LoopInfo>();
301 DT = &getAnalysis<DominatorTree>();
302 SE = &getAnalysis<ScalarEvolution>();
303
304 // Find all uses of induction variables in this loop, and categorize
305 // them by stride. Start by finding all of the PHI nodes in the header for
306 // this loop. If they are induction variables, inspect their uses.
307 for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
308 AddUsersIfInteresting(I);
309
| 266 } else {
267 StrideUses->addUser(Start, User, I);
268 }
269 }
270 }
271 return true;
272}
273
274void IVUsers::AddUser(const SCEV *Stride, const SCEV *Offset,
275 Instruction *User, Value *Operand) {
276 IVUsersOfOneStride *StrideUses = IVUsesByStride[Stride];
277 if (!StrideUses) { // First occurrence of this stride?
278 StrideOrder.push_back(Stride);
279 StrideUses = new IVUsersOfOneStride(Stride);
280 IVUses.push_back(StrideUses);
281 IVUsesByStride[Stride] = StrideUses;
282 }
283 IVUsesByStride[Stride]->addUser(Offset, User, Operand);
284}
285
286IVUsers::IVUsers()
287 : LoopPass(&ID) {
288}
289
290void IVUsers::getAnalysisUsage(AnalysisUsage &AU) const {
291 AU.addRequired<LoopInfo>();
292 AU.addRequired<DominatorTree>();
293 AU.addRequired<ScalarEvolution>();
294 AU.setPreservesAll();
295}
296
297bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) {
298
299 L = l;
300 LI = &getAnalysis<LoopInfo>();
301 DT = &getAnalysis<DominatorTree>();
302 SE = &getAnalysis<ScalarEvolution>();
303
304 // Find all uses of induction variables in this loop, and categorize
305 // them by stride. Start by finding all of the PHI nodes in the header for
306 // this loop. If they are induction variables, inspect their uses.
307 for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
308 AddUsersIfInteresting(I);
309
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310 Processed.clear();
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311 return false;
312}
313
314/// getReplacementExpr - Return a SCEV expression which computes the
315/// value of the OperandValToReplace of the given IVStrideUse.
316const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const {
317 // Start with zero.
318 const SCEV *RetVal = SE->getIntegerSCEV(0, U.getParent()->Stride->getType());
319 // Create the basic add recurrence.
320 RetVal = SE->getAddRecExpr(RetVal, U.getParent()->Stride, L);
321 // Add the offset in a separate step, because it may be loop-variant.
322 RetVal = SE->getAddExpr(RetVal, U.getOffset());
323 // For uses of post-incremented values, add an extra stride to compute
324 // the actual replacement value.
325 if (U.isUseOfPostIncrementedValue())
326 RetVal = SE->getAddExpr(RetVal, U.getParent()->Stride);
327 // Evaluate the expression out of the loop, if possible.
| 310 return false;
311}
312
313/// getReplacementExpr - Return a SCEV expression which computes the
314/// value of the OperandValToReplace of the given IVStrideUse.
315const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const {
316 // Start with zero.
317 const SCEV *RetVal = SE->getIntegerSCEV(0, U.getParent()->Stride->getType());
318 // Create the basic add recurrence.
319 RetVal = SE->getAddRecExpr(RetVal, U.getParent()->Stride, L);
320 // Add the offset in a separate step, because it may be loop-variant.
321 RetVal = SE->getAddExpr(RetVal, U.getOffset());
322 // For uses of post-incremented values, add an extra stride to compute
323 // the actual replacement value.
324 if (U.isUseOfPostIncrementedValue())
325 RetVal = SE->getAddExpr(RetVal, U.getParent()->Stride);
326 // Evaluate the expression out of the loop, if possible.
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328 if (!L->contains(U.getUser()->getParent())) {
| 327 if (!L->contains(U.getUser())) {
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329 const SCEV *ExitVal = SE->getSCEVAtScope(RetVal, L->getParentLoop());
330 if (ExitVal->isLoopInvariant(L))
331 RetVal = ExitVal;
332 }
333 return RetVal;
334}
335
336void IVUsers::print(raw_ostream &OS, const Module *M) const {
337 OS << "IV Users for loop ";
338 WriteAsOperand(OS, L->getHeader(), false);
339 if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
340 OS << " with backedge-taken count "
341 << *SE->getBackedgeTakenCount(L);
342 }
343 OS << ":\n";
344
345 for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e; ++Stride) {
346 std::map<const SCEV *, IVUsersOfOneStride*>::const_iterator SI =
347 IVUsesByStride.find(StrideOrder[Stride]);
348 assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
349 OS << " Stride " << *SI->first->getType() << " " << *SI->first << ":\n";
350
351 for (ilist<IVStrideUse>::const_iterator UI = SI->second->Users.begin(),
352 E = SI->second->Users.end(); UI != E; ++UI) {
353 OS << " ";
354 WriteAsOperand(OS, UI->getOperandValToReplace(), false);
355 OS << " = ";
356 OS << *getReplacementExpr(*UI);
357 if (UI->isUseOfPostIncrementedValue())
358 OS << " (post-inc)";
359 OS << " in ";
360 UI->getUser()->print(OS);
361 OS << '\n';
362 }
363 }
364}
365
366void IVUsers::dump() const {
| 328 const SCEV *ExitVal = SE->getSCEVAtScope(RetVal, L->getParentLoop());
329 if (ExitVal->isLoopInvariant(L))
330 RetVal = ExitVal;
331 }
332 return RetVal;
333}
334
335void IVUsers::print(raw_ostream &OS, const Module *M) const {
336 OS << "IV Users for loop ";
337 WriteAsOperand(OS, L->getHeader(), false);
338 if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
339 OS << " with backedge-taken count "
340 << *SE->getBackedgeTakenCount(L);
341 }
342 OS << ":\n";
343
344 for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e; ++Stride) {
345 std::map<const SCEV *, IVUsersOfOneStride*>::const_iterator SI =
346 IVUsesByStride.find(StrideOrder[Stride]);
347 assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
348 OS << " Stride " << *SI->first->getType() << " " << *SI->first << ":\n";
349
350 for (ilist<IVStrideUse>::const_iterator UI = SI->second->Users.begin(),
351 E = SI->second->Users.end(); UI != E; ++UI) {
352 OS << " ";
353 WriteAsOperand(OS, UI->getOperandValToReplace(), false);
354 OS << " = ";
355 OS << *getReplacementExpr(*UI);
356 if (UI->isUseOfPostIncrementedValue())
357 OS << " (post-inc)";
358 OS << " in ";
359 UI->getUser()->print(OS);
360 OS << '\n';
361 }
362 }
363}
364
365void IVUsers::dump() const {
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367 print(errs());
| 366 print(dbgs());
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368}
369
370void IVUsers::releaseMemory() {
371 IVUsesByStride.clear();
372 StrideOrder.clear();
| 367}
368
369void IVUsers::releaseMemory() {
370 IVUsesByStride.clear();
371 StrideOrder.clear();
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| 372 Processed.clear();
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373 IVUses.clear();
374}
375
376void IVStrideUse::deleted() {
377 // Remove this user from the list.
378 Parent->Users.erase(this);
379 // this now dangles!
380}
| 373 IVUses.clear();
374}
375
376void IVStrideUse::deleted() {
377 // Remove this user from the list.
378 Parent->Users.erase(this);
379 // this now dangles!
380}
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