[llvm-commits] [PATCH] Add Pattern ID Information

[Chris Lattner]

On Aug 3, 2011, at 4:38 PM, David Greene wrote:
> I've got a patch series ready to implement support for printing asm comments
> about instruction selection.  For example:
> 
>        incq    %rdx                    # test.c:38
>                                        #  Src: (add:i64 GR64:i64:$src, 1:i64)
>                                        #  Dst: (INC64r:i64 GR64:i64:$src)

Out of curiosity, how is this any better than just listing the 'INC64r' opcode?  We already have that accessible and don't need to add anything to MachineInstr to get it.

> This is really helpful for tracking down isel issues and was invaluable during
> AVX implementation and tuning.  So I want to get this in before I start doing
> the heavy-duty AVX merging.

What merging do you anticipate?  Mainline supports almost all of AVX, there are just a few bugs left and missed optimizations.

-Chris