[llvm-commits] [Please Review] [PATCH] optimization of -(x != 0) to use neg in X86

[Manman Ren]

PING

On May 3, 2012, at 7:14 PM, manman ren wrote:

> 
> X86: optimization for -(x != 0)
> 
> This patch will optimize -(x != 0) on X86
> FROM 
> cmpl	$0x01,%edi
> sbbl	%eax,%eax
> notl	%eax
> TO
> negl %edi
> sbbl %eax %eax
> 
> In order to generate negl, I added patterns in Target/X86/X86InstrCompiler.td:
> def : Pat<(X86sub_flag 0, GR32:$src), (NEG32r GR32:$src)>;
> 
> This is my first experience with tablegen, please review.
> The initial version of this patch (r155853) was the root cause of PR12720 and I did verify this patch against PR12720.
> 
> Thanks,
> Manman
> 
> <sext_ne.patch>
> 
> 
> 
> On Apr 30, 2012, at 11:38 AM, manman ren wrote:
> 
>>> 
>>> 
>>> On Apr 27, 2012, at 6:03 PM, manman ren wrote:
>>> 
>>>> 
>>>> This patch will optimize -(x != 0) on X86
>>>> FROM 
>>>> cmpl	$0x01,%edi
>>>> sbbl	%eax,%eax
>>>> notl	%eax
>>>> TO
>>>> negl %edi
>>>> sbbl %eax %eax
>>>> 
>>>> Please review & provide feedback,
>>>> Thanks,
>>>> Manman
>>>> 
>>>> <sext_ne.patch>
>>>> 
>>>> _______________________________________________
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>>>> llvm-commits at cs.uiuc.edu
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>>> 
>> 
>