[llvm] r246033 - [AArch64] Remove a use-after-free when collecting stats.

[Chad Rosier via llvm-commits]

Author: mcrosier
Date: Wed Aug 26 08:39:48 2015
New Revision: 246033

URL: http://llvm.org/viewvc/llvm-project?rev=246033&view=rev
Log:
[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.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp?rev=246033&r1=246032&r2=246033&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp Wed Aug 26 08:39:48 2015
@@ -984,15 +984,15 @@ bool AArch64LoadStoreOpt::optimizeBlock(
       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;