From: Owen Anderson <resistor@mac.com>
Date: Mon, 28 Jul 2008 16:00:58 +0000 (+0000)
Subject: Fix a subtle bug when removing instructions from memdep.  In very specific
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d4310a5d41cc13f109890f5efbb19e084fecb27a;p=oota-llvm.git

Fix a subtle bug when removing instructions from memdep.  In very specific
circumstances we could end up remapping a dependee to the same instruction
that we're trying to remove.  Handle this properly by just falling back to
a conservative solution.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54132 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 2012ab473c9..c93a680382e 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -528,6 +528,10 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction* rem) {
       // If we have dep info for rem, set them to it
       BasicBlock::iterator RI = depGraphEntry->second.first;
       RI++;
+      
+      // If RI is rem, then we use rem's immediate successor.
+      if (RI == (BasicBlock::iterator)rem) RI++;
+      
       newDep = RI;
     } else if ( (depGraphEntry->second.first == NonLocal ||
                  depGraphEntry->second.first == None ) &&