From: Philip Reames <listmail@philipreames.com>
Date: Thu, 14 Feb 2019 20:48:36 +0000 (+0000)
Subject: [InstCombine] Add todos for possible atomicrmw transforms
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2ecdf36fb1456dd69354966c2ce86e6f6d6294c6;p=llvm

[InstCombine] Add todos for possible atomicrmw transforms



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354059 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp b/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
index b607c6dd608..37c43977d90 100644
--- a/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAtomicRMW.cpp
@@ -51,6 +51,12 @@ bool isIdempotentRMW(AtomicRMWInst& RMWI) {
 
 
 Instruction *InstCombiner::visitAtomicRMWInst(AtomicRMWInst &RMWI) {
+  // TODO: Any atomicrmw op which produces a known result in memory can be
+  // replaced w/an atomicrmw xchg. (see getBinOpAbsorber)
+  
+  // TODO: Any atomicrmw xchg with no uses can be converted to a atomic store
+  // if the ordering is compatible.
+  
   if (!isIdempotentRMW(RMWI))
     return nullptr;