fix instcombine merging GEPs through a PHI to only make the
result inbounds if all of the inputs are inbounds.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125785 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombinePHI.cpp b/lib/Transforms/InstCombine/InstCombinePHI.cpp
index 736473d..a1aa2df 100644
--- a/lib/Transforms/InstCombine/InstCombinePHI.cpp
+++ b/lib/Transforms/InstCombine/InstCombinePHI.cpp
@@ -118,6 +118,8 @@
// especially bad when the PHIs are in the header of a loop.
bool NeededPhi = false;
+ bool AllInBounds = true;
+
// Scan to see if all operands are the same opcode, and all have one use.
for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) {
GetElementPtrInst *GEP= dyn_cast<GetElementPtrInst>(PN.getIncomingValue(i));
@@ -125,6 +127,8 @@
GEP->getNumOperands() != FirstInst->getNumOperands())
return 0;
+ AllInBounds &= GEP->isInBounds();
+
// Keep track of whether or not all GEPs are of alloca pointers.
if (AllBasePointersAreAllocas &&
(!isa<AllocaInst>(GEP->getOperand(0)) ||
@@ -202,11 +206,11 @@
}
Value *Base = FixedOperands[0];
- return cast<GEPOperator>(FirstInst)->isInBounds() ?
- GetElementPtrInst::CreateInBounds(Base, FixedOperands.begin()+1,
- FixedOperands.end()) :
+ GetElementPtrInst *NewGEP =
GetElementPtrInst::Create(Base, FixedOperands.begin()+1,
FixedOperands.end());
+ if (AllInBounds) NewGEP->setIsInbounds();
+ return NewGEP;
}