[all-commits] [llvm/llvm-project] 945ed2: [X86] Move the implicit enabling of sse2 for 64-bi...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 945ed22f3397f52469618cd8a94207665f25bebd
      https://github.com/llvm/llvm-project/commit/945ed22f3397f52469618cd8a94207665f25bebd
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-07-24 (Fri, 24 Jul 2020)

  Changed paths:
    M llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
    M llvm/lib/Target/X86/X86Subtarget.cpp

  Log Message:
  -----------
  [X86] Move the implicit enabling of sse2 for 64-bit mode from X86Subtarget::initSubtargetFeatures to X86_MC::ParseX86Triple.

ParseX86Triple already checks for 64-bit mode and produces a
static string. We can just add +sse2 to the end of that static
string. This avoids a potential reallocation when appending it
to the std::string at runtime.

This is a slight change to the behavior of tools that only use
MC layer which weren't implicitly enabling sse2 before, but will
now. I don't think we check for sse2 explicitly in any MC layer
components so this shouldn't matter in practice. And if it did
matter the new behavior is more correct.