[PATCH] D135957: [AArch64][SeperateConstOffsetFromGEP] Prevent pass from splitting GEP if an index has more than one use

Wed Oct 26 03:40:24 PDT 2022

zjaffal added a comment.

In D135957#3878970 <https://reviews.llvm.org/D135957#3878970>, @dmgreen wrote:

> Hmm. Should we be going further though? i.e why is it limited to the first index of a 2 element gep?

I am not sure if that would be beneficial. I can't think of an example multi index gep where all the geps are non constants. I can move the check inside the for loop and see if that changes any test cases this would be a good check at first.

> Should ConstantOffsetExtractor::Extract be considering the number of uses of the Add/Sub/Or is examines, and checking whether we are going to require duplicating instructions to separate the constant.

Do we need to eliminate any Add/Sub/OR that is used in instructions that aren't GEPs or that would be very strict?

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https://reviews.llvm.org/D135957