[all-commits] [llvm/llvm-project] 5106b2: [AArch64] Treat the icmp in icmp(and(..), 0) as free

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 5106b221c81a4d87d409379d06eb9d2a678e7b3d
      https://github.com/llvm/llvm-project/commit/5106b221c81a4d87d409379d06eb9d2a678e7b3d
  Author: David Green <david.green at arm.com>
  Date:   2023-07-01 (Sat, 01 Jul 2023)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
    M llvm/test/Analysis/CostModel/AArch64/cmp.ll

  Log Message:
  -----------
  [AArch64] Treat the icmp in icmp(and(..), 0) as free

As in https://godbolt.org/z/4dafd9Geq, the icmp from an And may use an Ands to
set flags, meaning the icmp is free.

This could also be done for add/sub, but those patterns often happen in the
induction variable of a loop, making them quite performance sensitive.

Differential Revision: https://reviews.llvm.org/D153611