From 6f83fc8afb7f31185a90f14a1b7dbf51492b0e92 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Mon, 24 Mar 2008 23:31:21 +0000
Subject: [PATCH] If the coalescer commuted a def MI to allow coalescing, it
 can changed a previously coalesced copy into an non-identity copy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48752 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SimpleRegisterCoalescing.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 6326edab349..6f5b5236386 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -323,7 +323,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
     MachineInstr *UseMI = &*UI;
     ++UI;
     if (JoinedCopies.count(UseMI))
-      continue;
+      // It'll no longer be "joined" after the change.
+      JoinedCopies.erase(UseMI);
     unsigned UseIdx = li_->getInstructionIndex(UseMI);
     LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
     if (ULR->valno != AValNo)