tree daab9f62e1da32dd7cc111261471a890d154ffa6
parent 41438be88af1a2ea003378a866447b4842990c69
author JF Bastien <jfb@google.com> 1444696127 +0000
committer JF Bastien <jfb@google.com> 1444696127 +0000

x86: preserve flags when folding atomic operations

Summary:
D4796 taught LLVM to fold some atomic integer operations into a single
instruction. The pattern was unaware that the instructions clobbered
flags.

This patch adds the missing EFLAGS definition.

Floating point operations don't set flags, the subsequent fadd
optimization is therefore correct. The same applies for surrounding
load/store optimizations.

Reviewers: rsmith, rtrieu

Subscribers: llvm-commits, reames, morisset

Differential Revision: http://reviews.llvm.org/D13680

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250135 91177308-0d34-0410-b5e6-96231b3b80d8