[PATCH] D89200: [X86] Add custom type legalization for i64 saddo/ssubo on 32-bit targets. Same for i128 on 64-bit targets.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: RKSimon, spatel, efriedma.
Herald added subscribers: pengfei, hiraditya.
Herald added a project: LLVM.
craig.topper requested review of this revision.

The default type legalization generates multiple compares to check
the overflow condition. But on X86 we can just emit an add/sub with
flags output followed by a adc/sbb and check the overflow flag.

I don't think the bug mentioned in the comment I removed applies
anymore. And if it is an issue I don't see why it wouldn't be
an issue with the expanded code we already get for UADDO/USUBO.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D89200

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/known-bits.ll
  llvm/test/CodeGen/X86/sadd_sat.ll
  llvm/test/CodeGen/X86/sadd_sat_plus.ll
  llvm/test/CodeGen/X86/sadd_sat_vec.ll
  llvm/test/CodeGen/X86/ssub_sat.ll
  llvm/test/CodeGen/X86/ssub_sat_plus.ll
  llvm/test/CodeGen/X86/ssub_sat_vec.ll
  llvm/test/CodeGen/X86/vec_saddo.ll
  llvm/test/CodeGen/X86/vec_ssubo.ll

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