Teach instcombine to respect and preserve inbounds. Add inbounds
to a few tests where it is required for the expected transformation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77290 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 9a53ea6..be43c55 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -213,7 +213,7 @@
Instruction *FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
ConstantInt *DivRHS);
- Instruction *FoldGEPICmp(User *GEPLHS, Value *RHS,
+ Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
ICmpInst::Predicate Cond, Instruction &I);
Instruction *FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
BinaryOperator &I);
@@ -5559,20 +5559,19 @@
/// FoldGEPICmp - Fold comparisons between a GEP instruction and something
/// else. At this point we know that the GEP is on the LHS of the comparison.
-Instruction *InstCombiner::FoldGEPICmp(User *GEPLHS, Value *RHS,
+Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
ICmpInst::Predicate Cond,
Instruction &I) {
- assert(isa<GEPOperator>(GEPLHS) && "LHS is not a getelementptr!");
-
// Look through bitcasts.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(RHS))
RHS = BCI->getOperand(0);
Value *PtrBase = GEPLHS->getOperand(0);
- if (TD && PtrBase == RHS) {
+ if (TD && PtrBase == RHS && GEPLHS->isInBounds()) {
// ((gep Ptr, OFFSET) cmp Ptr) ---> (OFFSET cmp 0).
// This transformation (ignoring the base and scales) is valid because we
- // know pointers can't overflow. See if we can output an optimized form.
+ // know pointers can't overflow since the gep is inbounds. See if we can
+ // output an optimized form.
Value *Offset = EvaluateGEPOffsetExpression(GEPLHS, I, *this);
// If not, synthesize the offset the hard way.
@@ -5580,7 +5579,7 @@
Offset = EmitGEPOffset(GEPLHS, I, *this);
return new ICmpInst(*Context, ICmpInst::getSignedPredicate(Cond), Offset,
Context->getNullValue(Offset->getType()));
- } else if (User *GEPRHS = dyn_cast<GEPOperator>(RHS)) {
+ } else if (GEPOperator *GEPRHS = dyn_cast<GEPOperator>(RHS)) {
// If the base pointers are different, but the indices are the same, just
// compare the base pointer.
if (PtrBase != GEPRHS->getOperand(0)) {
@@ -6345,10 +6344,10 @@
}
// If we can optimize a 'icmp GEP, P' or 'icmp P, GEP', do so now.
- if (User *GEP = dyn_cast<GEPOperator>(Op0))
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op0))
if (Instruction *NI = FoldGEPICmp(GEP, Op1, I.getPredicate(), I))
return NI;
- if (User *GEP = dyn_cast<GEPOperator>(Op1))
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1))
if (Instruction *NI = FoldGEPICmp(GEP, Op0,
ICmpInst::getSwappedPredicate(I.getPredicate()), I))
return NI;
@@ -8252,6 +8251,8 @@
NewIndices.end(), "");
InsertNewInstBefore(NGEP, CI);
NGEP->takeName(GEP);
+ if (cast<GEPOperator>(GEP)->isInBounds())
+ cast<GEPOperator>(NGEP)->setIsInBounds(true);
if (isa<BitCastInst>(CI))
return new BitCastInst(NGEP, CI.getType());
@@ -8981,8 +8982,11 @@
// If we found a path from the src to dest, create the getelementptr now.
if (SrcElTy == DstElTy) {
SmallVector<Value*, 8> Idxs(NumZeros+1, ZeroUInt);
- return GetElementPtrInst::Create(Src, Idxs.begin(), Idxs.end(), "",
- ((Instruction*) NULL));
+ Instruction *GEP = GetElementPtrInst::Create(Src,
+ Idxs.begin(), Idxs.end(), "",
+ ((Instruction*) NULL));
+ cast<GEPOperator>(GEP)->setIsInBounds(true);
+ return GEP;
}
}
@@ -10663,8 +10667,12 @@
}
Value *Base = FixedOperands[0];
- return GetElementPtrInst::Create(Base, FixedOperands.begin()+1,
- FixedOperands.end());
+ GetElementPtrInst *GEP =
+ GetElementPtrInst::Create(Base, FixedOperands.begin()+1,
+ FixedOperands.end());
+ if (cast<GEPOperator>(FirstInst)->isInBounds())
+ cast<GEPOperator>(GEP)->setIsInBounds(true);
+ return GEP;
}
@@ -11055,8 +11063,12 @@
// getelementptr instructions into a single instruction.
//
SmallVector<Value*, 8> SrcGEPOperands;
- if (User *Src = dyn_cast<GEPOperator>(PtrOp))
+ bool BothInBounds = cast<GEPOperator>(&GEP)->isInBounds();
+ if (GEPOperator *Src = dyn_cast<GEPOperator>(PtrOp)) {
SrcGEPOperands.append(Src->op_begin(), Src->op_end());
+ if (!Src->isInBounds())
+ BothInBounds = false;
+ }
if (!SrcGEPOperands.empty()) {
// Note that if our source is a gep chain itself that we wait for that
@@ -11140,9 +11152,15 @@
Indices.insert(Indices.end(), GEP.idx_begin()+1, GEP.idx_end());
}
- if (!Indices.empty())
- return GetElementPtrInst::Create(SrcGEPOperands[0], Indices.begin(),
- Indices.end(), GEP.getName());
+ if (!Indices.empty()) {
+ GetElementPtrInst *NewGEP = GetElementPtrInst::Create(SrcGEPOperands[0],
+ Indices.begin(),
+ Indices.end(),
+ GEP.getName());
+ if (BothInBounds)
+ cast<GEPOperator>(NewGEP)->setIsInBounds(true);
+ return NewGEP;
+ }
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(PtrOp)) {
// GEP of global variable. If all of the indices for this GEP are
@@ -11180,8 +11198,12 @@
if (CATy->getElementType() == XTy->getElementType()) {
// -> GEP i8* X, ...
SmallVector<Value*, 8> Indices(GEP.idx_begin()+1, GEP.idx_end());
- return GetElementPtrInst::Create(X, Indices.begin(), Indices.end(),
- GEP.getName());
+ GetElementPtrInst *NewGEP =
+ GetElementPtrInst::Create(X, Indices.begin(), Indices.end(),
+ GEP.getName());
+ if (cast<GEPOperator>(&GEP)->isInBounds())
+ cast<GEPOperator>(NewGEP)->setIsInBounds(true);
+ return NewGEP;
} else if (const ArrayType *XATy =
dyn_cast<ArrayType>(XTy->getElementType())) {
// GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
@@ -11208,8 +11230,11 @@
Value *Idx[2];
Idx[0] = Context->getNullValue(Type::Int32Ty);
Idx[1] = GEP.getOperand(1);
- Value *V = InsertNewInstBefore(
- GetElementPtrInst::Create(X, Idx, Idx + 2, GEP.getName()), GEP);
+ GetElementPtrInst *NewGEP =
+ GetElementPtrInst::Create(X, Idx, Idx + 2, GEP.getName());
+ if (cast<GEPOperator>(&GEP)->isInBounds())
+ cast<GEPOperator>(NewGEP)->setIsInBounds(true);
+ Value *V = InsertNewInstBefore(NewGEP, GEP);
// V and GEP are both pointer types --> BitCast
return new BitCastInst(V, GEP.getType());
}
@@ -11271,6 +11296,8 @@
Idx[1] = NewIdx;
Instruction *NewGEP =
GetElementPtrInst::Create(X, Idx, Idx + 2, GEP.getName());
+ if (cast<GEPOperator>(&GEP)->isInBounds())
+ cast<GEPOperator>(NewGEP)->setIsInBounds(true);
NewGEP = InsertNewInstBefore(NewGEP, GEP);
// The NewGEP must be pointer typed, so must the old one -> BitCast
return new BitCastInst(NewGEP, GEP.getType());
@@ -11323,6 +11350,8 @@
GetElementPtrInst::Create(BCI->getOperand(0), NewIndices.begin(),
NewIndices.end());
if (NGEP->getType() == GEP.getType()) return NGEP;
+ if (cast<GEPOperator>(&GEP)->isInBounds())
+ cast<GEPOperator>(NGEP)->setIsInBounds(true);
InsertNewInstBefore(NGEP, GEP);
NGEP->takeName(&GEP);
return new BitCastInst(NGEP, GEP.getType());
@@ -11366,6 +11395,7 @@
Idx[1] = NullIdx;
Value *V = GetElementPtrInst::Create(New, Idx, Idx + 2,
New->getName()+".sub", It);
+ cast<GEPOperator>(V)->setIsInBounds(true);
// Now make everything use the getelementptr instead of the original
// allocation.
@@ -11745,6 +11775,7 @@
CastOp = IC.InsertNewInstBefore(
GetElementPtrInst::Create(CastOp, NewGEPIndices.begin(),
NewGEPIndices.end()), SI);
+ cast<GEPOperator>(CastOp)->setIsInBounds(true);
}
if (Constant *C = dyn_cast<Constant>(SIOp0))
@@ -12428,6 +12459,7 @@
Context->getPointerType(EI.getType(), AS),EI);
GetElementPtrInst *GEP =
GetElementPtrInst::Create(Ptr, EI.getOperand(1), I->getName()+".gep");
+ cast<GEPOperator>(GEP)->setIsInBounds(true);
InsertNewInstBefore(GEP, EI);
return new LoadInst(GEP);
}