[llvm-dev] How to use FileCheck to check that two registers are different

[Tom Stellard via llvm-dev]

On 05/31/2017 09:17 PM, Mark Searles via llvm-dev wrote:
> Can FileCheck be used to check that two registers are not the same?
> 
> Context: the AMDGPU v_qsad_pk_u16_8 instructions looks like this:
> v_qsad_pk_u16_8 dst, src0, src1, src2
> 
> The destination register must be different than the source registers. I know how how to check that, say, src2 is the same as the dst register but not how to check that src2 is not the same as the dst register.
> 
> Here's my initial try, but as you can see it'll pass, rather than fail, if dst and src2 are the same.
>  v_qsad_pk_u16_u8 [[DEST:v\[[0-9]+:[0-9]+\]]], s[{{[0-9]+:[0-9]+}}], v{{[0-9]+}}, [[DEST]]
> 
> Thanks for any suggestions,
> 

You can use the CHECK-NOT: label to tell it to fail if it matches the pattern.

-Tom

> Mark
> 
> 
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