Allow unordered loads to be considered invariant in CodeGen
The actual code change is fairly straight forward, but exercising it isn't. First, it turned out we weren't adding the appropriate flags in SelectionDAG. Second, it turned out that we've got some optimization gaps, so obvious test cases don't work.
My first attempt (in atomic-unordered.ll) points out a deficiency in our peephole-opt folding logic which I plan to fix separately. Instead, I'm exercising this through MachineLICM.
Differential Revision: https://reviews.llvm.org/D59375
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356494
91177308-0d34-0410-b5e6-
96231b3b80d8
OSDN Git Service
