[AliasAnalysis] Fences do not modify constant memory location
Summary:
Fence instructions are currently marked as `ModRef` for all memory locations.
We can improve this for constant memory locations (such as constant globals),
since fence instructions cannot modify these locations.
This helps us to forward constant loads across fences (added test case in GVN).
There were no changes in behaviour for similar test cases in early-cse and licm.
Reviewers: dberlin, sanjoy, reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28914
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292546
91177308-0d34-0410-b5e6-
96231b3b80d8
projects / llvm / commit