diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/TargetLowering.cpp | 6 | ||||
| -rw-r--r-- | test/CodeGen/X86/2009-06-15-not-a-tail-call.ll | 14 |
2 files changed, 19 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp index ab4cd51553..134a859ceb 100644 --- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -2584,8 +2584,12 @@ bool TargetLowering::CheckTailCallReturnConstraints(CallSDNode *TheCall, // Check that operand of the RET node sources from the CALL node. The RET node // has at least two operands. Operand 0 holds the chain. Operand 1 holds the // value. + // Also we need to check that there is no code in between the call and the + // return. Hence we also check that the incomming chain to the return sources + // from the outgoing chain of the call. if (NumOps > 1 && - IgnoreHarmlessInstructions(Ret.getOperand(1)) == SDValue(TheCall,0)) + IgnoreHarmlessInstructions(Ret.getOperand(1)) == SDValue(TheCall,0) && + Ret.getOperand(0) == SDValue(TheCall, TheCall->getNumValues()-1)) return true; // void return: The RET node has the chain result value of the CALL node as // input. diff --git a/test/CodeGen/X86/2009-06-15-not-a-tail-call.ll b/test/CodeGen/X86/2009-06-15-not-a-tail-call.ll new file mode 100644 index 0000000000..095e6a1036 --- /dev/null +++ b/test/CodeGen/X86/2009-06-15-not-a-tail-call.ll @@ -0,0 +1,14 @@ +; RUN: llvm-as < %s | llc -march=x86 -tailcallopt | not grep TAILCALL + +; Bug 4396. This tail call can NOT be optimized. + +declare fastcc i8* @_D3gcx2GC12mallocNoSyncMFmkZPv() nounwind + +define fastcc i8* @_D3gcx2GC12callocNoSyncMFmkZPv() nounwind { +entry: + %tmp6 = tail call fastcc i8* @_D3gcx2GC12mallocNoSyncMFmkZPv() ; <i8*> [#uses=2] + %tmp9 = tail call i8* @memset(i8* %tmp6, i32 0, i64 2) ; <i8*> [#uses=0] + ret i8* %tmp6 +} + +declare i8* @memset(i8*, i32, i64) |