Daniel Berlin abebf8ad17 AliasAnalysis: Be less conservative about volatile than atomic. ... Summary: getModRefInfo is meant to answer the question "what impact does this instruction have on a given memory location" (not even another instruction). Long debate on this on IRC comes to the conclusion the answer should be "nothing special". That is, a noalias volatile store does not affect a memory location just by being volatile. Note: DSE and GVN and memdep currently believe this, because memdep just goes behind AA's back after it says "modref" right now. see line 635 of memdep. Prior to this patch we would get modref there, then check aliasing, and if it said noalias, we would continue. getModRefInfo *already* has this same AA check, it just wasn't being used because volatile was lumped in with ordering. (I am separately testing whether this code in memdep is now dead except for the invariant load case) Reviewers: jyknight, chandlerc Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D31726 llvm-svn: 299741		2017-04-07 01:28:36 +00:00
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llvm	AliasAnalysis: Be less conservative about volatile than atomic.	2017-04-07 01:28:36 +00:00
llvm-c	Split the SimplifyCFG pass into two variants.	2017-03-26 06:44:08 +00:00