Don't let a noalias difference disrupt the tailcall optimization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88672 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2009-11-13 18:49:38 +00:00
parent 0d1680a7d8
commit 01205a80f5
2 changed files with 19 additions and 4 deletions

View File

@@ -4349,7 +4349,7 @@ SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
/// TargetLowering::IsEligibleForTailCallOptimization.
///
static bool
isInTailCallPosition(const Instruction *I, Attributes RetAttr,
isInTailCallPosition(const Instruction *I, Attributes CalleeRetAttr,
const TargetLowering &TLI) {
const BasicBlock *ExitBB = I->getParent();
const TerminatorInst *Term = ExitBB->getTerminator();
@@ -4377,8 +4377,9 @@ isInTailCallPosition(const Instruction *I, Attributes RetAttr,
if (!Ret || Ret->getNumOperands() == 0) return true;
// Conservatively require the attributes of the call to match those of
// the return.
if (F->getAttributes().getRetAttributes() != RetAttr)
// the return. Ignore noalias because it doesn't affect the call sequence.
unsigned CallerRetAttr = F->getAttributes().getRetAttributes();
if ((CalleeRetAttr ^ CallerRetAttr) & ~Attribute::NoAlias)
return false;
// Otherwise, make sure the unmodified return value of I is the return value.