[all-commits] [llvm/llvm-project] 802826: Recommit "[ConstraintElim] Enable pass by default."

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8028263c41e335bc96c40402f8ab44ad405023de
      https://github.com/llvm/llvm-project/commit/8028263c41e335bc96c40402f8ab44ad405023de
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2023-02-06 (Mon, 06 Feb 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-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-pgo-defaults.ll
    M llvm/test/Other/new-pm-thinlto-prelink-samplepgo-defaults.ll

  Log Message:
  -----------
  Recommit "[ConstraintElim] Enable pass by default."

This reverts commit 695ce48c63ec582a46bfbda9b066f4d3bcde143f.

The compile-time regression causing the revert has been fixed. Recommit
the original patch.

Original commit message:

   The pass should help to close a functional gap when it comes to
    reasoning about related conditions in a relatively general way.

    It addresses multiple existing issues (linked below) and the need for a
    more powerful reasoning system was also discussed recently in
    https://discourse.llvm.org/t/rfc-alternative-approach-of-dealing-with-implications-from-comparisons-through-pos-analysis/65601/7

    On AArch64, the new pass performs ~2000 simplifications on
    MultiSource,SPEC2006,SPEC2017 with -O3.

    Compile-time impact:

    NewPM-O3: +0.20%
    NewPM-ReleaseThinLTO: +0.32%
    NewPM-ReleaseLTO-g: +0.28%

    https://llvm-compile-time-tracker.com/compare.php?from=f01a3a893c147c1594b9a3fbd817456b209dabbf&to=577688758ef64fb044215ec3e497ea901bb2db28&stat=instructions:u

    Fixes #49344.
    Fixes #47888.
    Fixes #48253.
    Fixes #49229.
    Fixes #58074.

    Reviewed By: asbirlea

    Differential Revision: https://reviews.llvm.org/D135915