[PATCH] D57803: [X86][GlobalISEL] Support lowering aligned unordered atomics

[Philip Reames via Phabricator via llvm-commits]

reames created this revision.
reames added reviewers: jlebar, kzhuravl, stoklund, dsanders, igorb.
Herald added subscribers: Petar.Avramovic, jfb, bollu, kristof.beyls, rovka, mcrosier.

This is a companion to D57601 <https://reviews.llvm.org/D57601>, but will be landed afterwards.  I don't want to have to worry about two sources of atomic MMOs, some volatile, some not.

The existing lowering code is accidentally correct for unordered atomics as far as I can tell.  An unordered atomic has no memory ordering, and simply requires the actual load or store to be done as a single well aligned instruction.  As such, relax the restriction while adding tests to ensure the lowering remains correct in the future.


https://reviews.llvm.org/D57803

Files:
  lib/Target/X86/X86InstructionSelector.cpp
  test/CodeGen/X86/atomic-unordered.ll

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