[PATCH] D99565: [X86] Support replacing aligned vector moves with unaligned moves when avx is enabled.

Tue Apr 13 00:58:23 PDT 2021

LiuChen3 added a comment.

In D99565#2678073 <https://reviews.llvm.org/D99565#2678073>, @craig.topper wrote:

> I think I wouldn't mind if we just didn't emit aligned loads/store instructions for AVX/AVX512 from isel and other places in the compiler in the first place. As noted, if the load gets folded the alignment check doesn't happen. That would reduce the size of the isel tables and remove branches, reducing complexity of the compiler. Adding a new step and a command line to undo the earlier decision increases complexity.
>
> The counter argument to that is that the alignment check has found bugs in the vectorizer on more than one occasion that I know of.

Hi, @craig.topper. I'm not sure if I understand what you mean correctly. Do you mean we can remove the alignload/alignstore pattern match so that we can reduce the size of the isel tables? But this means that there is no option to control this behavior.

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https://reviews.llvm.org/D99565