[PATCH] D42646: [X86] Avoid using high register trick for test instruction

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

Potentially, but the flag usage is tricky. We can't turn TEST32 into TEST8 if the sign flag is being used. We are guaranteed safe if bit 15 of the immediate is clear. But if bit 15 is set we'd need to check flag users.


Repository:
  rL LLVM

https://reviews.llvm.org/D42646