[llvm-commits] [llvm] r171524 - in /llvm/trunk: lib/Target/X86/CMakeLists.txt lib/Target/X86/X86.h lib/Target/X86/X86.td lib/Target/X86/X86PadShortFunction.cpp lib/Target/X86/X86Subtarget.cpp lib/Target/X86/X86Subtarget.h lib/Target/X86/X86TargetMa...

[Zhang, Andy]

Hi Nadav,

I believe that the Peephole Optimizer pass is too early to do this optimization since scheduling may cause the NOOPs to be rearranged so that they are no longer right before the RET. Looking at the passes, I can't find one after post-RA scheduling that looks appropriate. Would you be able to suggest another pass to put this in?

Thanks,
Andy

> -----Original Message-----
> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
> bounces at cs.uiuc.edu] On Behalf Of Nadav Rotem
> Sent: Friday, January 04, 2013 4:14 PM
> To: Gurd, Preston
> Cc: llvm-commits at cs.uiuc.edu
> Subject: Re: [llvm-commits] [llvm] r171524 - in /llvm/trunk:
> lib/Target/X86/CMakeLists.txt lib/Target/X86/X86.h lib/Target/X86/X86.td
> lib/Target/X86/X86PadShortFunction.cpp lib/Target/X86/X86Subtarget.cpp
> lib/Target/X86/X86Subtarget.h lib/Target/X86/X86TargetMa...
> 
> Preston,  I am not sure that adding a new pass is the right way to go.
> Have you considered writing a simple peephole ?
> 
> Nadav
>