[llvm-commits] [llvm] r151877 - in /llvm/trunk: lib/Target/X86/X86ISelLowering.cpp test/CodeGen/X86/sibcall-5.ll

[Evan Cheng]

On Mar 1, 2012, at 6:50 PM, Chad Rosier wrote:

> 
> 
> +  // If anything is glued to the copy, then we can't safely perform a tail call.
> +  if (Copy->getOpcode() == ISD::CopyToReg &&
> +      Copy->getNumOperands() == 4)
> +    return false;

Hi Chad,

This is not the right way to check whether anything is glued to the copy. It's checking whether the copytoreg has a 4th argument and the use magic number is fragile. You want to check if the copytoreg has second value and whether that value has any use.

Also since the code fragment before is:

  if (Copy->getOpcode() != ISD::CopyToReg &&
      Copy->getOpcode() != ISD::FP_EXTEND)
    return false;

You want to write something like

  if (Copy->getOpcode() != ISD::CopyToReg) {
	// If anything is glued to the copy ...
  } else if (Copy->getOpcode() != ISD::FP_EXTEND)
    return false;


Evan

> +
>   bool HasRet = false;
>   for (SDNode::use_iterator UI = Copy->use_begin(), UE = Copy->use_end();
>        UI != UE; ++UI) {
> 
> Modified: llvm/trunk/test/CodeGen/X86/sibcall-5.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sibcall-5.ll?rev=151877&r1=151876&r2=151877&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/sibcall-5.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/sibcall-5.ll Thu Mar  1 20:50:46 2012
> @@ -1,5 +1,6 @@
> ; RUN: llc < %s -mtriple=i386-apple-darwin8 -mattr=+sse2  | FileCheck %s --check-prefix=X32
> ; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=+sse2 | FileCheck %s --check-prefix=X64
> +; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=-sse3 | FileCheck %s --check-prefix=X64_BAD
> 
> ; Sibcall optimization of expanded libcalls.
> ; rdar://8707777
> @@ -29,3 +30,31 @@
> declare float @sinf(float) nounwind readonly
> 
> declare double @sin(double) nounwind readonly
> +
> +; rdar://10930395
> +%0 = type opaque
> +
> +@"\01L_OBJC_SELECTOR_REFERENCES_2" = external hidden global i8*, section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip"
> +
> +define hidden { double, double } @foo2(%0* %self, i8* nocapture %_cmd) uwtable optsize ssp {
> +; X64_BAD: foo
> +; X64_BAD: call
> +; X64_BAD: call
> +; X64_BAD: call
> +  %1 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_2", align 8, !invariant.load !0
> +  %2 = bitcast %0* %self to i8*
> +  %3 = tail call { double, double } bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to { double, double } (i8*, i8*)*)(i8* %2, i8* %1) optsize
> +  %4 = extractvalue { double, double } %3, 0
> +  %5 = extractvalue { double, double } %3, 1
> +  %6 = tail call double @floor(double %4) optsize
> +  %7 = tail call double @floor(double %5) optsize
> +  %insert.i.i = insertvalue { double, double } undef, double %6, 0
> +  %insert5.i.i = insertvalue { double, double } %insert.i.i, double %7, 1
> +  ret { double, double } %insert5.i.i
> +}
> +
> +declare i8* @objc_msgSend(i8*, i8*, ...)
> +
> +declare double @floor(double) optsize
> +
> +!0 = metadata !{}
> 
> 
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