[llvm-commits] [llvm] r56674 - /llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp

[Owen Anderson]

Author: resistor
Date: Fri Sep 26 13:50:46 2008
New Revision: 56674

URL: http://llvm.org/viewvc/llvm-project?rev=56674&view=rev
Log:
We don't need to insert copies for implicit_def's.

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=56674&r1=56673&r2=56674&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp (original)
+++ llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp Fri Sep 26 13:50:46 2008
@@ -419,7 +419,6 @@
   MachineBasicBlock::iterator P = MBB->begin();
   while (P != MBB->end() && P->getOpcode() == TargetInstrInfo::PHI) {
     unsigned DestReg = P->getOperand(0).getReg();
-
     
     // Don't both doing PHI elimination for dead PHI's.
     if (P->registerDefIsDead(DestReg)) {
@@ -448,6 +447,11 @@
         ProcessedNames.insert(SrcReg);
         continue;
       }
+      
+      // We don't need to insert copies for implicit_defs.
+      MachineInstr* DefMI = MRI.getVRegDef(SrcReg);
+      if (DefMI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF)
+        ProcessedNames.insert(SrcReg);
     
       // Check for trivial interferences via liveness information, allowing us
       // to avoid extra work later.  Any registers that interfere cannot both