[all-commits] [llvm/llvm-project] 44b260: [X86] Increase the number of instructions searched...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 44b260cb0aab387d85e4d59c16fc7b8866264f5e
      https://github.com/llvm/llvm-project/commit/44b260cb0aab387d85e4d59c16fc7b8866264f5e
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-08-08 (Sat, 08 Aug 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86FixupLEAs.cpp
    M llvm/lib/Target/X86/X86InstrInfo.cpp
    M llvm/lib/Target/X86/X86InstrInfo.h
    M llvm/test/CodeGen/X86/optimize-max-0.ll

  Log Message:
  -----------
  [X86] Increase the number of instructions searched for isSafeToClobberEFLAGS in a couple places

Previously this function searched 4 instructions forwards or
backwards to determine if it was ok to clobber eflags.

This is called in 3 places: rematerialization, turning 2 operand
leas into adds or splitting 3 ops leas into an lea and add on some
CPU targets.

This patch increases the search limit to 10 instructions for
rematerialization and 2 operand lea to add. I've left the old
treshold for 3 ops lea spliting as that increases code size.

Fixes PR47024 and PR43014