[llvm-commits] [llvm] r152492 - /llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp

[Benjamin Kramer]

Author: d0k
Date: Sat Mar 10 06:50:44 2012
New Revision: 152492

URL: http://llvm.org/viewvc/llvm-project?rev=152492&view=rev
Log:
Microoptimize getVRegDef. def_begin isn't free, don't compute it twice.

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

Modified: llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp?rev=152492&r1=152491&r2=152492&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp Sat Mar 10 06:50:44 2012
@@ -161,9 +161,8 @@
 /// form, so there should only be one definition.
 MachineInstr *MachineRegisterInfo::getVRegDef(unsigned Reg) const {
   // Since we are in SSA form, we can use the first definition.
-  if (!def_empty(Reg))
-    return &*def_begin(Reg);
-  return 0;
+  def_iterator I = def_begin(Reg);
+  return !I.atEnd() ? &*I : 0;
 }
 
 bool MachineRegisterInfo::hasOneUse(unsigned RegNo) const {