[PATCH] D18572: [AArch64] Relax branches by fusing compare with conditional branch when we can infer that source register is zero/non-zero.

[Geoff Berry via llvm-commits]

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Hi Balaram,

I'm not sure I understand why this is being done so late in the pipeline.  It seems to me like we could catch these cases much earlier.

This also seems related to the patch http://reviews.llvm.org/D7708, which I believe would allow this case to be caught much earlier in instsimplify (perhaps requiring a bit of work in instsimplify as well).  This code was recently removed for lack of evidence of its benefit, but it might be worthwhile to evaluate it in the context of this particular optimization.


http://reviews.llvm.org/D18572