[llvm] r210168 - Fix a use of uninitialized value. OldCC is set when IsCmpZero || IsSwapped and read when ShouldUpdateCC || IsSwapped, and ShouldUpdateCC is independent. Fixes PR19932, but no test since I wasn't able to get any symptoms to appear, not even with valgrind and the testcase from the PR. It's clear what happened from inspection of the code.

[Nick Lewycky]

Author: nicholas
Date: Wed Jun  4 02:45:54 2014
New Revision: 210168

URL: http://llvm.org/viewvc/llvm-project?rev=210168&view=rev
Log:
Fix a use of uninitialized value. OldCC is set when IsCmpZero || IsSwapped and read when ShouldUpdateCC || IsSwapped, and ShouldUpdateCC is independent. Fixes PR19932, but no test since I wasn't able to get any symptoms to appear, not even with valgrind and the testcase from the PR. It's clear what happened from inspection of the code.

Modified:
    llvm/trunk/lib/Target/X86/X86InstrInfo.cpp

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=210168&r1=210167&r2=210168&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Wed Jun  4 02:45:54 2014
@@ -3741,7 +3741,7 @@ optimizeCompareInstr(MachineInstr *CmpIn
       continue;
 
     // EFLAGS is used by this instruction.
-    X86::CondCode OldCC;
+    X86::CondCode OldCC = X86::COND_INVALID;
     bool OpcIsSET = false;
     if (IsCmpZero || IsSwapped) {
       // We decode the condition code from opcode.