diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp index b3d8d1dbee6..f2c623cd616 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp @@ -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. diff --git a/test/CodeGen/X86/tailcall1.ll b/test/CodeGen/X86/tailcall1.ll index a4f87c021a9..215d00946dd 100644 --- a/test/CodeGen/X86/tailcall1.ll +++ b/test/CodeGen/X86/tailcall1.ll @@ -1,4 +1,4 @@ -; RUN: llc < %s -march=x86 -tailcallopt | grep TAILCALL +; RUN: llc < %s -march=x86 -tailcallopt | grep TAILCALL | count 3 define fastcc i32 @tailcallee(i32 %a1, i32 %a2, i32 %a3, i32 %a4) { entry: ret i32 %a3 @@ -9,3 +9,17 @@ entry: %tmp11 = tail call fastcc i32 @tailcallee( i32 %in1, i32 %in2, i32 %in1, i32 %in2 ) ; [#uses=1] ret i32 %tmp11 } + +declare fastcc i8* @alias_callee() + +define fastcc noalias i8* @noalias_caller() nounwind { + %p = tail call fastcc i8* @alias_callee() + ret i8* %p +} + +declare fastcc noalias i8* @noalias_callee() + +define fastcc i8* @alias_caller() nounwind { + %p = tail call fastcc noalias i8* @noalias_callee() + ret i8* %p +}