From 2c64130c4320b2bb53db71f737faadd0cc493cd3 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Sun, 16 Aug 2009 11:56:42 +0000
Subject: [PATCH] Fix use after free in Thumb2SizeReduction (PR4707). A
 MachineInstr was used after erasure.

llvm-svn: 79189
---
 llvm/lib/Target/ARM/Thumb2SizeReduction.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/ARM/Thumb2SizeReduction.cpp b/llvm/lib/Target/ARM/Thumb2SizeReduction.cpp
index b3ed8e84f920..e6f45bb5ca9d 100644
--- a/llvm/lib/Target/ARM/Thumb2SizeReduction.cpp
+++ b/llvm/lib/Target/ARM/Thumb2SizeReduction.cpp
@@ -654,8 +654,11 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
       }
 
       // Try to transform ro a 16-bit non-two-address instruction.
-      if (Entry.NarrowOpc1 && ReduceToNarrow(MBB, MI, Entry, LiveCPSR))
+      if (Entry.NarrowOpc1 && ReduceToNarrow(MBB, MI, Entry, LiveCPSR)) {
         Modified = true;
+        MachineBasicBlock::iterator I = prior(NextMII);
+        MI = &*I;
+      }
     }
 
   ProcessNext: