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

[manman ren]

Chad,

Thanks for pointing that out. Updated patch is attached.

I have the "commit after approval" access now.

Thanks for your help,
Manman


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On Apr 30, 2012, at 9:58 AM, Chad Rosier wrote:

> Manman,
> 
> +      if (ConstantSDNode *YC = dyn_cast<ConstantSDNode>(Y))
> +        if (YC && YC->isNullValue() && 
> +            (isAllOnes(Op1) == (CondCode == X86::COND_NE))) {
> 
> The dyn_cast<> operator returns null if the operand is not of the correct type.  Thus, the "YC &&" check is not necessary.
> 
> Chad
> 
> 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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>