diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index ff4a283b58..9b985f94ad 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -2525,16 +2525,29 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, if (RegInfo->needsStackRealignment(MF)) return false; - // Do not sibcall optimize vararg calls unless the call site is not passing - // any arguments. - if (isVarArg && !Outs.empty()) - return false; - // Also avoid sibcall optimization if either caller or callee uses struct // return semantics. if (isCalleeStructRet || isCallerStructRet) return false; + // Do not sibcall optimize vararg calls unless all arguments are passed via + // registers + if (isVarArg && !Outs.empty()) { + SmallVector<CCValAssign, 16> ArgLocs; + CCState CCInfo(CalleeCC, isVarArg, getTargetMachine(), + ArgLocs, *DAG.getContext()); + + // Allocate shadow area for Win64 + if (Subtarget->isTargetWin64()) { + CCInfo.AllocateStack(32, 8); + } + + CCInfo.AnalyzeCallOperands(Outs, CC_X86); + for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) + if (!ArgLocs[i].isRegLoc()) + return false; + } + // If the call result is in ST0 / ST1, it needs to be popped off the x87 stack. // Therefore if it's not used by the call it is not safe to optimize this into // a sibcall. |