From: Nick Lewycky <nicholas@mxc.ca>
Date: Wed, 4 Jun 2014 07:45:54 +0000 (+0000)
Subject: Fix a use of uninitialized value. OldCC is set when IsCmpZero || IsSwapped and read... 
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0a9a866ce1b0b59af324d2001689ca89b6957e98;p=platform%2Fupstream%2Fllvm.git

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.

llvm-svn: 210168
---

diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index 6993577..a0ee1ee 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -3741,7 +3741,7 @@ optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2,
       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.