[all-commits] [llvm/llvm-project] fb13dc: [ConstraintElim] Enable pass by default.

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: fb13dcf3431cd83911fe56899d2fade808dc5b8d
      https://github.com/llvm/llvm-project/commit/fb13dcf3431cd83911fe56899d2fade808dc5b8d
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2023-01-04 (Wed, 04 Jan 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:
  -----------
  [ConstraintElim] Enable pass by default.

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