Fix one bug in the latest incarnation of r209843 -- combining GEPs
across PHI nodes. The code was computing the Idxs from the 'GEP'
variable's indices when what it wanted was Op1's indices. This caused an
ASan heap-overflow for me that pin pointed the issue when Op1 had more
indices than GEP did. =] I'll let Louis add a specific test case for
this if he wants.
llvm-svn: 209857
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index c72d099..38f92dd 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1233,10 +1233,21 @@
if (!Op2 || Op1->getNumOperands() != Op2->getNumOperands())
return nullptr;
+ // Keep track of the type as we walk the GEP.
+ Type *CurTy = Op1->getOperand(0)->getType()->getScalarType();
+
for (unsigned J = 0, F = Op1->getNumOperands(); J != F; ++J) {
if (Op1->getOperand(J)->getType() != Op2->getOperand(J)->getType())
return nullptr;
+ if (J > 1) {
+ if (CompositeType *CT = dyn_cast<CompositeType>(CurTy)) {
+ CurTy = CT->getTypeAtIndex(Op1->getOperand(J));
+ } else {
+ CurTy = nullptr;
+ }
+ }
+
if (Op1->getOperand(J) != Op2->getOperand(J)) {
if (DI == -1) {
// We have not seen any differences yet in the GEPs feeding the
@@ -1245,14 +1256,8 @@
// The first two arguments can vary for any GEP, the rest have to be
// static for struct slots
- if (J > 1) {
- SmallVector<Value*, 8> Idxs(GEP.idx_begin(), GEP.idx_begin()+J-1);
- Type *Ty =
- GetElementPtrInst::getIndexedType(Op1->getOperand(0)->getType(),
- Idxs);
- if (Ty->isStructTy())
- return nullptr;
- }
+ if (J > 1 && CurTy->isStructTy())
+ return nullptr;
DI = J;
} else {