diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 55 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/tailcall2.ll | 13 |
2 files changed, 62 insertions, 6 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index a8308b80a96..d05de21be3d 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -1807,6 +1807,10 @@ X86TargetLowering::LowerCall(SDValue Chain, SDValue Callee, unsigned NumBytes = CCInfo.getNextStackOffset(); if (FuncIsMadeTailCallSafe(CallConv)) NumBytes = GetAlignedArgumentStackSize(NumBytes, DAG); + else if (isTailCall && !PerformTailCallOpt) + // This is a sibcall. The memory operands are available in caller's + // own caller's stack. + NumBytes = 0; int FPDiff = 0; if (isTailCall) { @@ -1976,9 +1980,11 @@ X86TargetLowering::LowerCall(SDValue Chain, SDValue Callee, int FI = 0; // Do not flag preceeding copytoreg stuff together with the following stuff. InFlag = SDValue(); - for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { - CCValAssign &VA = ArgLocs[i]; - if (!VA.isRegLoc()) { + if (PerformTailCallOpt) { + for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { + CCValAssign &VA = ArgLocs[i]; + if (VA.isRegLoc()) + continue; assert(VA.isMemLoc()); SDValue Arg = Outs[i].Val; ISD::ArgFlagsTy Flags = Outs[i].Flags; @@ -2259,11 +2265,14 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, return false; } + + // Look for obvious safe cases to perform tail call optimization that does not + // requite ABI changes. This is what gcc calls sibcall. + // Do not tail call optimize vararg calls for now. if (isVarArg) return false; - // Look for obvious safe cases to perform tail call optimization. // If the callee takes no arguments then go on to check the results of the // call. if (!Outs.empty()) { @@ -2273,8 +2282,42 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, CCState CCInfo(CalleeCC, isVarArg, getTargetMachine(), ArgLocs, *DAG.getContext()); CCInfo.AnalyzeCallOperands(Outs, CCAssignFnForNode(CalleeCC)); - if (CCInfo.getNextStackOffset()) - return false; + if (CCInfo.getNextStackOffset()) { + MachineFunction &MF = DAG.getMachineFunction(); + if (MF.getInfo<X86MachineFunctionInfo>()->getBytesToPopOnReturn()) + return false; + if (Subtarget->isTargetWin64()) + // Win64 ABI has additional complications. + return false; + + // Check if the arguments are already laid out in the right way as + // the caller's fixed stack objects. + MachineFrameInfo *MFI = MF.getFrameInfo(); + for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { + CCValAssign &VA = ArgLocs[i]; + EVT RegVT = VA.getLocVT(); + SDValue Arg = Outs[i].Val; + ISD::ArgFlagsTy Flags = Outs[i].Flags; + if (Flags.isByVal()) + return false; // TODO + if (VA.getLocInfo() == CCValAssign::Indirect) + return false; + if (!VA.isRegLoc()) { + LoadSDNode *Ld = dyn_cast<LoadSDNode>(Arg); + if (!Ld) + return false; + SDValue Ptr = Ld->getBasePtr(); + FrameIndexSDNode *FINode = dyn_cast<FrameIndexSDNode>(Ptr); + if (!FINode) + return false; + int FI = FINode->getIndex(); + if (!MFI->isFixedObjectIndex(FI)) + return false; + if (VA.getLocMemOffset() != MFI->getObjectOffset(FI)) + return false; + } + } + } } // If the caller does not return a value, then this is obviously safe. diff --git a/llvm/test/CodeGen/X86/tailcall2.ll b/llvm/test/CodeGen/X86/tailcall2.ll index 1e288f57651..e41e3da4f80 100644 --- a/llvm/test/CodeGen/X86/tailcall2.ll +++ b/llvm/test/CodeGen/X86/tailcall2.ll @@ -89,3 +89,16 @@ bb1: } declare i32 @bar(i32) + +define i32 @t7(i32 %a, i32 %b, i32 %c) nounwind ssp { +entry: +; 32: t7: +; 32: jmp {{_?}}bar2 + +; 64: t7: +; 64: jmp {{_?}}bar2 + %0 = tail call i32 @bar2(i32 %a, i32 %b, i32 %c) nounwind + ret i32 %0 +} + +declare i32 @bar2(i32, i32, i32) |
