[all-commits] [llvm/llvm-project] 05a2f4: [AggressiveInstCombine] Enable also for -O2

[Dávid Bolvanský via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 05a2f4290e27c67b0f547b893f1dc9aaf6d40ca2
      https://github.com/llvm/llvm-project/commit/05a2f4290e27c67b0f547b893f1dc9aaf6d40ca2
  Author: Dávid Bolvanský <david.bolvansky at gmail.com>
  Date:   2023-04-05 (Wed, 05 Apr 2023)

  Changed paths:
    M llvm/lib/Passes/PassBuilderPipelines.cpp
    M llvm/test/Other/new-pm-defaults.ll
    M llvm/test/Other/new-pm-lto-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-pgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-postlink-samplepgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-pgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-samplepgo-defaults.ll

  Log Message:
  -----------
  [AggressiveInstCombine] Enable also for -O2

Next step after https://reviews.llvm.org/D113179

Recently a set of patches by @anton-afanasyev improved many cases (better and cleaner vectorized code) thanks to improvements to AIC's TruncInstCombine (IC cannot handle it) motivated by real examples in bug reports. There was a discussion that -O2 could benefit from AIC as well, but discussion then stalled, so I would like restart it, with new numbers from LLVM compile time tracker.

As -O2 pipeline is not tracked by LLVM compile time tracker, I disabled AIC for -O3 to get an idea how expensive is it. Without AIC, I observed that geomean was cca -0.10%. Given that it seems like AIC is quite cheap, heavily tested by -O3 pipeline, I am proposing to enable it also with -O2 and similar to improve quality to vectorized code.

https://llvm-compile-time-tracker.com/compare.php?from=a1df5abef5f27646c809c7b85cf6170eb68f7735&to=e1ba6068f58c6ca862b920b8750faccb42a5843c&stat=instructions:u

Differential Revision: https://reviews.llvm.org/D147604
Reviewed-By: nikic