[llvm] r199214 - Fix valgrind warning for gcc builds.

[Patrik Hagglund]

Author: patha
Date: Tue Jan 14 08:09:00 2014
New Revision: 199214

URL: http://llvm.org/viewvc/llvm-project?rev=199214&view=rev
Log:
Fix valgrind warning for gcc builds.

Sorry, I don't understand why the warning is generated (a gcc
bug?). Anyhow, the change should improve readablity. No functionality
change intended.

Modified:
    llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp

Modified: llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp?rev=199214&r1=199213&r2=199214&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp Tue Jan 14 08:09:00 2014
@@ -816,18 +816,17 @@ bool RegisterCoalescer::reMaterializeTri
   }
 
   if (TargetRegisterInfo::isVirtualRegister(DstReg)) {
-    unsigned NewIdx = NewMI->getOperand(0).getSubReg();
+    unsigned NewIdx;
     const TargetRegisterClass *RCForInst;
-    if (NewIdx)
-      RCForInst = TRI->getMatchingSuperRegClass(MRI->getRegClass(DstReg), DefRC,
-                                                NewIdx);
 
     if (MRI->constrainRegClass(DstReg, DefRC)) {
       // The materialized instruction is quite capable of setting DstReg
       // directly, but it may still have a now-trivial subregister index which
       // we should clear.
       NewMI->getOperand(0).setSubReg(0);
-    } else if (NewIdx && RCForInst) {
+    } else if ((NewIdx = NewMI->getOperand(0).getSubReg()) &&
+               (RCForInst = TRI->getMatchingSuperRegClass(
+                 MRI->getRegClass(DstReg), DefRC, NewIdx))) {
       // The subreg index on NewMI is essential; we still have to make sure
       // DstReg:idx is in a class that NewMI can use.
       MRI->constrainRegClass(DstReg, RCForInst);