[llvm-commits] CVS: llvm/lib/CodeGen/RegAllocLocal.cpp

[Chris Lattner]

Changes in directory llvm/lib/CodeGen:

RegAllocLocal.cpp updated: 1.75 -> 1.76
---
Log message:

Nuke noop copies.


---
Diffs of the changes:  (+11 -4)

 RegAllocLocal.cpp |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)


Index: llvm/lib/CodeGen/RegAllocLocal.cpp
diff -u llvm/lib/CodeGen/RegAllocLocal.cpp:1.75 llvm/lib/CodeGen/RegAllocLocal.cpp:1.76
--- llvm/lib/CodeGen/RegAllocLocal.cpp:1.75	Tue Nov  8 23:28:45 2005
+++ llvm/lib/CodeGen/RegAllocLocal.cpp	Wed Nov  9 12:22:42 2005
@@ -488,9 +488,11 @@
 
 void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
   // loop over each instruction
-  MachineBasicBlock::iterator MI = MBB.begin();
-  for (; MI != MBB.end(); ++MI) {
-    const TargetInstrDescriptor &TID = TM->getInstrInfo()->get(MI->getOpcode());
+  MachineBasicBlock::iterator MII = MBB.begin();
+  const TargetInstrInfo &TII = *TM->getInstrInfo();
+  while (MII != MBB.end()) {
+    MachineInstr *MI = MII++;
+    const TargetInstrDescriptor &TID = TII.get(MI->getOpcode());
     DEBUG(std::cerr << "\nStarting RegAlloc of: " << *MI;
           std::cerr << "  Regs have values: ";
           for (unsigned i = 0; i != RegInfo->getNumRegs(); ++i)
@@ -621,9 +623,14 @@
         removePhysReg(PhysReg);
       }
     }
+    
+    // Finally, if this is a noop copy instruction, zap it.
+    unsigned SrcReg, DstReg;
+    if (TII.isMoveInstr(*MI, SrcReg, DstReg) && SrcReg == DstReg)
+      MBB.erase(MI);
   }
 
-  MI = MBB.getFirstTerminator();
+  MachineBasicBlock::iterator MI = MBB.getFirstTerminator();
 
   // Spill all physical registers holding virtual registers now.
   for (unsigned i = 0, e = RegInfo->getNumRegs(); i != e; ++i)