[PATCH] D138242: [RISCV] Use register allocation hints to improve use of compressed instructions.

[Luís Marques via Phabricator via llvm-commits]

luismarques added a comment.

I was assuming this would never increase code size but that didn't seem to be the case. Since it wasn't clear to me why that would be, I reduced a problematic case and the conclusion is... it's because it's incomplete. The new register allocation sometimes ends up being unfavorable for the compressible instructions that are not yet handled (obvious in hindsight). I presume that once this code is complete that will either go away or be much more unlikely. Still, even as it is, the typical result is to improve code size so it's a nice improvement!

I suggest fleshing out the compressibility test a bit more.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D138242/new/

https://reviews.llvm.org/D138242