From: Chad Rosier <mcrosier@codeaurora.org>
Date: Wed, 26 Aug 2015 13:39:48 +0000 (+0000)
Subject: [AArch64] Remove a use-after-free when collecting stats.
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=cd619e4031e8d5d7dd248c175f0da2821c9b22a3

[AArch64] Remove a use-after-free when collecting stats.

The call to mergePairedInsns() deletes MI, so the later use by isUnscaledLdSt()
is referencing freed memory.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246033 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp b/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
index b67d2e2acf9..f7f3bfa7595 100644
--- a/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
+++ b/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
@@ -984,15 +984,15 @@ bool AArch64LoadStoreOpt::optimizeBlock(MachineBasicBlock &MBB) {
       MachineBasicBlock::iterator Paired =
           findMatchingInsn(MBBI, Flags, ScanLimit);
       if (Paired != E) {
+        ++NumPairCreated;
+        if (isUnscaledLdSt(MI))
+          ++NumUnscaledPairCreated;
+
         // Merge the loads into a pair. Keeping the iterator straight is a
         // pain, so we let the merge routine tell us what the next instruction
         // is after it's done mucking about.
         MBBI = mergePairedInsns(MBBI, Paired, Flags);
-
         Modified = true;
-        ++NumPairCreated;
-        if (isUnscaledLdSt(MI))
-          ++NumUnscaledPairCreated;
         break;
       }
       ++MBBI;