[all-commits] [llvm/llvm-project] 992b45: [Utils][UnifyLoopExits] Avoid costly updates if no...

[Johannes Doerfert via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 992b451f0837b08961b4aa5dab5e90bc2443b482
      https://github.com/llvm/llvm-project/commit/992b451f0837b08961b4aa5dab5e90bc2443b482
  Author: Johannes Doerfert <johannes at jdoerfert.de>
  Date:   2025-02-28 (Fri, 28 Feb 2025)

  Changed paths:
    M llvm/include/llvm/Transforms/Utils/ControlFlowUtils.h
    M llvm/lib/Transforms/Utils/ControlFlowUtils.cpp
    M llvm/lib/Transforms/Utils/UnifyLoopExits.cpp
    M llvm/test/CodeGen/AMDGPU/GlobalISel/divergence-divergent-i1-used-outside-loop.ll
    M llvm/test/CodeGen/AMDGPU/local-atomicrmw-fadd.ll
    M llvm/test/CodeGen/AMDGPU/no-fold-accvgpr-mov.ll

  Log Message:
  -----------
  [Utils][UnifyLoopExits] Avoid costly updates if nothing changed (#129179)

If the ControlFlowHub did not perform any change to the control flow,
there is no need to repair SSA, update the loop structure, and verify a
bunch of things. This is not completely NFC though, repairSSA introduced
PHI nodes with a single entry that are now missing.

My code went from 400+ seconds to 1 second, since no loop required the
exits to be unified, but there were many "complex" loops.



To unsubscribe from these emails, change your notification settings at https://github.com/llvm/llvm-project/settings/notifications