[PATCH] D31726: AliasAnalysis: Be less conservative about volatile than atomic.
Daniel Berlin via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Apr 5 15:06:01 PDT 2017
dberlin added inline comments.
================
Comment at: lib/Analysis/AliasAnalysis.cpp:336
+ // Be conservative in the face of atomic.
+ if (isStrongerThan(L->getOrdering(), AtomicOrdering::NotAtomic))
return MRI_ModRef;
----------------
sanjoy wrote:
> Why not `isStrongerThan(L->getOrdering(), AtomicOrdering::Unordered)`? (same below)
>
> OTOH I'm surprised that this did not break any tests.
Honestly:
Because i don't know enough to know if that's okay ;)
If it is, happy to do it.
It breaks 1 optimizations test that i'm looking at:
memcpy/atomic.ll optimizes *less* now.
Which makes no sense at all. I suspect it was relying on weird aliasing before. I'm debugging.
Otherwise, it does break some memoryssa tests, which i'm updating for the correct answers.
(i'm also still awaiting 3 stage results on linux)
https://reviews.llvm.org/D31726
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