Changes in directory llvm/lib/VMCore:
ConstantFolding.cpp updated: 1.83 -> 1.84
---
Log message:
constant fold extractelement with undef operands.
---
Diffs of the changes: (+7 -1)
ConstantFolding.cpp | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletion(-)
Index: llvm/lib/VMCore/ConstantFolding.cpp
diff -u llvm/lib/VMCore/ConstantFolding.cpp:1.83
llvm/lib/VMCore/ConstantFolding.cpp:1.84
--- llvm/lib/VMCore/ConstantFolding.cpp:1.83 Tue Jan 17 14:07:22 2006
+++ llvm/lib/VMCore/ConstantFolding.cpp Fri Mar 31 12:31:40 2006
@@ -726,11 +726,17 @@
Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val,
const Constant *Idx) {
+ if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
+ return UndefValue::get(cast<PackedType>(Val->getType())->getElementType());
+
if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) {
if (const ConstantUInt *CIdx = dyn_cast<ConstantUInt>(Idx)) {
return const_cast<Constant*>(CVal->getOperand(CIdx->getValue()));
+ } else if (isa<UndefValue>(Idx)) {
+ // ee({w,x,y,z}, undef) -> w (an arbitrary value).
+ return const_cast<Constant*>(CVal->getOperand(0));
}
- }
+ }
return 0;
}
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