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
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