[PATCH] D141712: [GVN] Improve PRE on load instructions

Tue Mar 21 18:35:09 PDT 2023

Carrot added a comment.

@nikic, the original version of this patch is 0.07% slower because more triggered optimizations caused more iterations on huge functions.
http://llvm-compile-time-tracker.com/compare.php?from=d38d6065584ee5dd837e9a629f90c731d8a7dffc&to=94fc2022ff32b63d6c744d3eeff4f304e1a81618&stat=instructions:u

The second version is 0.16% slower because it leaves the dead instructions to next iteration, so it causes an extra iteration on whole function. http://llvm-compile-time-tracker.com/compare.php?from=287508cd9c4396c8845d92310d258879202a179e&to=5f1448fe1585b5677d5f0064e4eeac3b493d8a18&stat=instructions%3Au

The current version is 0.08% slower, very close to the first version. This time I record the BBs contain dead stores, instead of revisit the whole function, I just revisit these recorded BBs. http://llvm-compile-time-tracker.com/compare.php?from=c8e5354f0063b090b6fa7ad4cfc2b9df78038454&to=d21dbfa65423bbd9251ab5948f6cc1baa2db61c8&stat=instructions:u.

Is it OK now?
Thanks.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D141712/new/

https://reviews.llvm.org/D141712