[all-commits] [llvm/llvm-project] c41b41: [LoopVectorize] Use overflow-check analysis to imp...

[sdesmalen-arm via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c41b41eb11b4e6debf2f1bfb2b1d637b209a14c2
      https://github.com/llvm/llvm-project/commit/c41b41eb11b4e6debf2f1bfb2b1d637b209a14c2
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2023-03-01 (Wed, 01 Mar 2023)

  Changed paths:
    M llvm/include/llvm/Analysis/TargetTransformInfo.h
    M llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
    M llvm/include/llvm/CodeGen/BasicTTIImpl.h
    M llvm/lib/Analysis/TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.h
    M llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence-fold-tail.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/sve-low-trip-count.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/sve-tail-folding-optsize.ll
    A llvm/test/Transforms/LoopVectorize/AArch64/sve-tail-folding-overflow-checks.ll
    M llvm/test/Transforms/LoopVectorize/RISCV/low-trip-count.ll
    M llvm/test/Transforms/LoopVectorize/RISCV/scalable-tailfold.ll
    M llvm/test/Transforms/LoopVectorize/RISCV/short-trip-count.ll
    M llvm/test/Transforms/LoopVectorize/RISCV/uniform-load-store.ll

  Log Message:
  -----------
  [LoopVectorize] Use overflow-check analysis to improve tail-folding.

This work follows on from D142109 and addresses a possible regression
when we know the loop iteration counter cannot overflow.

When we know the overflow-check always evaluates to false, it's better to
use the other style of tail folding where it assumes a runtime check was
added, because that avoids having to calculate a modified trip-count.

Reviewed By: paulwalker-arm

Differential Revision: https://reviews.llvm.org/D142894