[PATCH] D58875: [X86] Merge negated ISD::SUB nodes into X86ISD::SUB equivalent (PR40483) (WIP)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: spatel, craig.topper.
Herald added a project: LLVM.

Follow up to D58597 <https://reviews.llvm.org/D58597>, where I mentioned that the commuted ISD::SUB variant was having problems with lack of combines.

Any advice on how best to fix these regressions? Do we have a mechanism to propagate EFLAGS changes if we commute a X86ISD::SUB?


Repository:
  rL LLVM

https://reviews.llvm.org/D58875

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/combine-sbb.ll
  test/CodeGen/X86/jump_sign.ll

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