Transforms/InstCombine/InstCombineCompares.cpp

145 Instruction *InstCombiner::foldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
161   // Require: GEP GV, 0, i {{, constant indices}}
162   if (GEP->getNumOperands() < 3 ||
163       !isa<ConstantInt>(GEP->getOperand(1)) ||
164       !cast<ConstantInt>(GEP->getOperand(1))->isZero() ||
165       isa<Constant>(GEP->getOperand(2)))
174   for (unsigned i = 3, e = GEP->getNumOperands(); i != e; ++i) {
175     ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(i));
308   Value *Idx = GEP->getOperand(2);
311   // index down like the GEP would do implicitly.  We don't have to do this for
312   // an inbounds GEP because the index can't be out of range.
313   if (!GEP->isInBounds()) {
314     Type *IntPtrTy = DL.getIntPtrType(GEP->getType());
415 /// Return a value that can be used to compare the *offset* implied by a GEP to
425 static Value *evaluateGEPOffsetExpression(User *GEP, InstCombiner &IC,
427   gep_type_iterator GTI = gep_type_begin(GEP);
431   // in terms of the scale of the variable index.  For example, if the GEP
434   unsigned i, e = GEP->getNumOperands();
437     if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) {
458   Value *VariableIdx = GEP->getOperand(i);
465     ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i));
483   Type *IntPtrTy = DL.getIntPtrType(GEP->getOperand(0)->getType());
516 /// Returns true if we can rewrite Start as a GEP with pointer Base
562       if (auto *GEP = dyn_cast<GEPOperator>(V)) {
563         // We're limiting the GEP to having one index. This will preserve
566         if (GEP->getNumIndices() != 1 || !GEP->isInBounds() ||
567             GEP->getType() != Start->getType())
570         if (Explored.count(GEP->getOperand(0)) == 0)
571           WorkList.push_back(GEP->getOperand(0));
641 /// Returns a re-written value of Start as an indexed GEP using Base as a
684     if (auto *GEP = dyn_cast<GEPOperator>(Val)) {
685       Value *Index = NewInsts[GEP->getOperand(1)] ? NewInsts[GEP->getOperand(1)]
686                                                   : GEP->getOperand(1);
687       setInsertionPoint(Builder, GEP);
691           NewInsts[GEP->getOperand(0)]->getType()->getScalarSizeInBits()) {
693             Index, NewInsts[GEP->getOperand(0)]->getType(),
694             GEP->getOperand(0)->getName() + ".sext");
697       auto *Op = NewInsts[GEP->getOperand(0)];
699         NewInsts[GEP] = Index;
701         NewInsts[GEP] = Builder.CreateNSWAdd(
702             Op, Index, GEP->getOperand(0)->getName() + ".add");
735     // a GEP or a GEP + ptrtoint.
744     Value *GEP = Builder.CreateInBoundsGEP(
749       Value *Cast = Builder.CreatePointerCast(GEP, Val->getType(),
751       GEP = Cast;
753     Val->replaceAllUsesWith(GEP);
760 /// the input Value as a constant indexed GEP. Returns a pair containing
769     if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
772       if (!GEP->isInBounds())
774       if (GEP->hasAllConstantIndices() && GEP->getNumIndices() == 1 &&
775           GEP->getType() == V->getType()) {
776         V = GEP->getOperand(0);
777         Constant *GEPIndex = static_cast<Constant *>(GEP->getOperand(1));
836   // GEP having PtrBase as the pointer base, and has returned in NewRHS the
842 /// Fold comparisons between a GEP instruction and something else. At this point
843 /// we know that the GEP is on the LHS of the comparison.
848   // GEP is inbounds, the final add of the base pointer can have signed overflow
968     // If the other GEP has all zero indices, recurse.
996       if (NumDifferences == 0)   // SAME GEP?
1008     // Only lower this if the icmp is the only user of the GEP or if we expect
1837     if (auto *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0)))
1838       if (auto *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
1842           if (Instruction *Res = foldCmpLoadFromIndexedGlobal(GEP, GV, Cmp, C2))
3177     // icmp pred GEP (P, int 0, int 0, int 0), null -> icmp pred P, null
3251     if (GetElementPtrInst *GEP =
3253       if (GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
3256           if (Instruction *Res = foldCmpLoadFromIndexedGlobal(GEP, GV, I))
5563   // If we can optimize a 'icmp GEP, P' or 'icmp P, GEP', do so now.
5564   if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op0))
5565     if (Instruction *NI = foldGEPICmp(GEP, Op1, I.getPredicate(), I))
5567   if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1))
5568     if (Instruction *NI = foldGEPICmp(GEP, Op0,
6139       if (auto *GEP = dyn_cast<GetElementPtrInst>(LHSI->getOperand(0)))
6140         if (auto *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
6143             if (Instruction *Res = foldCmpLoadFromIndexedGlobal(GEP, GV, I))