diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index bc29df49810..55de3d3c98a 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -2814,7 +2814,7 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, const SmallVectorImpl &Outs, const SmallVectorImpl &OutVals, const SmallVectorImpl &Ins, - SelectionDAG& DAG) const { + SelectionDAG &DAG) const { if (!IsTailCallConvention(CalleeCC) && CalleeCC != CallingConv::C) return false; @@ -2853,7 +2853,7 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, // An stdcall caller is expected to clean up its arguments; the callee // isn't going to do that. - if (!CCMatch && CallerCC==CallingConv::X86_StdCall) + if (!CCMatch && CallerCC == CallingConv::X86_StdCall) return false; // Do not sibcall optimize vararg calls unless all arguments are passed via @@ -2973,9 +2973,15 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, // callee-saved registers are restored. These happen to be the same // registers used to pass 'inreg' arguments so watch out for those. if (!Subtarget->is64Bit() && - !isa(Callee) && - !isa(Callee)) { + ((!isa(Callee) && + !isa(Callee)) || + getTargetMachine().getRelocationModel() == Reloc::PIC_)) { unsigned NumInRegs = 0; + // In PIC we need an extra register to formulate the address computation + // for the callee. + unsigned MaxInRegs = + (getTargetMachine().getRelocationModel() == Reloc::PIC_) ? 2 : 3; + for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { CCValAssign &VA = ArgLocs[i]; if (!VA.isRegLoc()) @@ -2984,7 +2990,7 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, switch (Reg) { default: break; case X86::EAX: case X86::EDX: case X86::ECX: - if (++NumInRegs == 3) + if (++NumInRegs == MaxInRegs) return false; break; }