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
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index b3d8d1d..f2c623c 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -4349,7 +4349,7 @@
/// 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 @@
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.