[all-commits] [llvm/llvm-project] 875f0c: [ARM] Optimize fp store of extract to integer stor...

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 875f0cbcc6d5ff9b36e667911e96fcdf6afc698e
      https://github.com/llvm/llvm-project/commit/875f0cbcc6d5ff9b36e667911e96fcdf6afc698e
  Author: David Green <david.green at arm.com>
  Date:   2021-02-12 (Fri, 12 Feb 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMISelLowering.cpp
    M llvm/test/CodeGen/Thumb2/mve-extractstore.ll
    M llvm/test/CodeGen/Thumb2/mve-float16regloops.ll

  Log Message:
  -----------
  [ARM] Optimize fp store of extract to integer store if already available.

Given a floating point store from an extracted vector, with an integer
VGETLANE that already exists, storing the existing VGETLANEu directly
can be better for performance. As the value is known to already be in an
integer registers, this can help reduce fp register pressure, removed
the need for the fp extract and allows use of more integer post-inc
stores not available with vstr.

This can be a bit narrow in scope, but helps with certain biquad kernels
that store shuffled vector elements.

Differential Revision: https://reviews.llvm.org/D96159