[PATCH] D110867: X86InstrInfo: Support immediates that are +1/-1 different in optimizeCompareInstr

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

Thanks for reporting!

> I suspect what's happening is that this transformation figures the second cmp is redundant if it changes "jle bar" to "jl bar", but it doesn't take into account that the "je baz" was also depending on that second cmp.

The optimization should have detected EFLAGS being live out of the bar block in your example and abort because there could potentially be more users (see line 4550).

Is there a way to reproduce this easily?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110867/new/

https://reviews.llvm.org/D110867