Anna Thomas aaeaea1399 [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

2017-01-20 00:21:33 +00:00

..

llvm

[AliasAnalysis] Fences do not modify constant memory location

2017-01-20 00:21:33 +00:00

llvm-c

[GVN] Initial check-in of a new global value numbering algorithm.

2016-12-22 16:03:48 +00:00