[PATCH] D143129: [GVN] Do not propagate equalities for noalias pointers

Mon Feb 20 16:09:08 PST 2023

mnadeem added a comment.

In D143129#4125424 <https://reviews.llvm.org/D143129#4125424>, @nikic wrote:

>> Here are the diffs for llvm-test-suite bitcode:
>> https://github.com/UsmanNadeem/vigilant-octo-journey/commit/125698f591df1f8de81ad4119b0838e135a18af8
>> and
>> https://github.com/UsmanNadeem/vigilant-octo-journey/commit/a778479334852e7f05b5a248da4473106aa986fb
>
> ...
> Oh, that's a nice way to analyze differences. How did you produce the output?
> ...

I compiled the test suite using -O3 with the base toolchain and made a list of files where GVN did pointer replacements by adding some debug output in that function. Copied the compile commands for those files from the make output and then used those to dump the IR for the base toolchain and toolchains with various patches.

Discourse link:  https://discourse.llvm.org/t/restricting-equality-propagation-for-pointers-whats-the-best-way-how-to-deal-with-regressions/68619

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D143129/new/

https://reviews.llvm.org/D143129