[all-commits] [llvm/llvm-project] 091244: [ARM] Move VPTBlock pass after post-ra scheduling

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 091244023ac38df3d99c99005d695602b1747454
      https://github.com/llvm/llvm-project/commit/091244023ac38df3d99c99005d695602b1747454
  Author: David Green <david.green at arm.com>
  Date:   2021-11-04 (Thu, 04 Nov 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMTargetMachine.cpp
    M llvm/test/CodeGen/ARM/O3-pipeline.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/arm_cmplx_dot_prod_f32.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/cond-vector-reduce-mve-codegen.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/fast-fp-loops.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/mve-tail-data-types.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/reductions.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/spillingmove.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/tail-pred-disabled-in-loloops.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/unpredload.ll
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/varying-outer-2d-reduction.ll
    M llvm/test/CodeGen/Thumb2/active_lane_mask.ll
    M llvm/test/CodeGen/Thumb2/mve-blockplacement.ll
    M llvm/test/CodeGen/Thumb2/mve-float16regloops.ll
    M llvm/test/CodeGen/Thumb2/mve-gather-increment.ll
    M llvm/test/CodeGen/Thumb2/mve-gather-ind16-scaled.ll
    M llvm/test/CodeGen/Thumb2/mve-gather-scatter-tailpred.ll
    M llvm/test/CodeGen/Thumb2/mve-masked-ldst-offset.ll
    M llvm/test/CodeGen/Thumb2/mve-masked-ldst-postinc.ll
    M llvm/test/CodeGen/Thumb2/mve-masked-ldst-preinc.ll
    M llvm/test/CodeGen/Thumb2/mve-postinc-dct.ll
    M llvm/test/CodeGen/Thumb2/mve-pred-constfold.ll
    M llvm/test/CodeGen/Thumb2/mve-pred-vctpvpsel.ll
    M llvm/test/CodeGen/Thumb2/mve-satmul-loops.ll
    M llvm/test/CodeGen/Thumb2/mve-scatter-increment.ll
    M llvm/test/CodeGen/Thumb2/mve-tailpred-loopinvariant.ll
    M llvm/test/CodeGen/Thumb2/mve-vctp.ll
    M llvm/test/CodeGen/Thumb2/mve-vecreduce-addpred.ll
    M llvm/test/CodeGen/Thumb2/mve-vecreduce-mlapred.ll
    M llvm/test/CodeGen/Thumb2/mve-vmaxnma-tailpred.ll
    M llvm/test/CodeGen/Thumb2/mve-vmovlloop.ll
    M llvm/test/CodeGen/Thumb2/mve-zext-masked-load.ll

  Log Message:
  -----------
  [ARM] Move VPTBlock pass after post-ra scheduling

Currently when tail predicating loops, vpt blocks need to be created
with the vctp predicate in case we need to revert to non-tail predicated
form. This has the unfortunate side effect of severely hampering post-ra
scheduling at times as the instructions are already stuck in vpt blocks,
not allowed to be independently ordered.

This patch addresses that by just moving the creation of VPT blocks
later in the pipeline, after post-ra scheduling has been performed. This
allows more optimal scheduling post-ra before the vpt blocks are
created, leading to more optimal tail predicated loops.

Differential Revision: https://reviews.llvm.org/D113094