[llvm-commits] [llvm] r122596 - /llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp

[Cameron Zwarich]

Author: zwarich
Date: Tue Dec 28 04:49:33 2010
New Revision: 122596

URL: http://llvm.org/viewvc/llvm-project?rev=122596&view=rev
Log:
Avoid iterating every operand of an instruction in StrongPHIElimination, since
we are only interested in the defs when discovering interferences.

This is a 28% speedup running StrongPHIElimination on 403.gcc.

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

Modified: llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp?rev=122596&r1=122595&r2=122596&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp (original)
+++ llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp Tue Dec 28 04:49:33 2010
@@ -471,10 +471,9 @@
     DenseMap<unsigned, unsigned>& ImmediateDominatingParent) {
   for (MachineBasicBlock::iterator BBI = MBB.begin(), BBE = MBB.end();
   BBI != BBE; ++BBI) {
-    for (unsigned i = 0, e = BBI->getNumOperands(); i != e; ++i) {
-      MachineOperand& MO = BBI->getOperand(i);
-      if (!MO.isReg() || !MO.isDef())
-        continue;
+    for (MachineInstr::const_mop_iterator I = BBI->operands_begin(),
+         E = BBI->operands_end(); I != E && I->isReg() && I->isDef(); ++I) {
+      const MachineOperand& MO = *I;
 
       unsigned DestReg = MO.getReg();
       if (!DestReg || !TargetRegisterInfo::isVirtualRegister(DestReg))