From 670ed09238453f2d6614086b0a2d72bed180a8d2 Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Thu, 18 Sep 2008 23:04:18 +0000
Subject: Decrementing the iterator here could be wrong if the worklist is
 empty after the "erase". Thanks to Ji Young Park for the patch!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56316 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/DCE.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

(limited to 'lib/Transforms')

diff --git a/lib/Transforms/Scalar/DCE.cpp b/lib/Transforms/Scalar/DCE.cpp
index cb78207d76..fb9a0e04fd 100644
--- a/lib/Transforms/Scalar/DCE.cpp
+++ b/lib/Transforms/Scalar/DCE.cpp
@@ -111,11 +111,12 @@ bool DCE::runOnFunction(Function &F) {
 
       // Remove the instruction from the worklist if it still exists in it.
       for (std::vector<Instruction*>::iterator WI = WorkList.begin();
-           WI != WorkList.end(); ++WI)
-        if (*WI == I) {
+           WI != WorkList.end(); ) {
+        if (*WI == I)
           WI = WorkList.erase(WI);
-          --WI;
-        }
+        else
+          ++WI;
+      }
 
       MadeChange = true;
       ++DCEEliminated;
-- 
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