[all-commits] [llvm/llvm-project] 24b3c2: [BreakFalseDeps] Harden pickBestRegisterForUndef a...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 24b3c2d0585f2f96574e9819313ab05e8943ee02
      https://github.com/llvm/llvm-project/commit/24b3c2d0585f2f96574e9819313ab05e8943ee02
  Author: Craig Topper <craig.topper at gmail.com>
  Date:   2020-05-09 (Sat, 09 May 2020)

  Changed paths:
    M llvm/lib/CodeGen/BreakFalseDeps.cpp

  Log Message:
  -----------
  [BreakFalseDeps] Harden pickBestRegisterForUndef against changing tied operands or physical registers that aren't renamable.

I don't have any test cases since X86 doesn't return any tied
operands from getUndefRegClearance today. But conceivably we could
want BreakFalseDeps to insert a dependency breaking XOR for
a tied operand in the future.