[llvm-commits] [llvm] r125226 - /llvm/trunk/lib/CodeGen/SplitKit.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Wed Feb  9 15:52:09 2011
New Revision: 125226

URL: http://llvm.org/viewvc/llvm-project?rev=125226&view=rev
Log:
Ignore <undef> uses when analyzing and rewriting.

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

Modified: llvm/trunk/lib/CodeGen/SplitKit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SplitKit.cpp?rev=125226&r1=125225&r2=125226&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SplitKit.cpp (original)
+++ llvm/trunk/lib/CodeGen/SplitKit.cpp Wed Feb  9 15:52:09 2011
@@ -64,8 +64,12 @@
 /// analyzeUses - Count instructions, basic blocks, and loops using CurLI.
 void SplitAnalysis::analyzeUses() {
   const MachineRegisterInfo &MRI = MF.getRegInfo();
-  for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(CurLI->reg);
-       MachineInstr *MI = I.skipInstruction();) {
+  for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(CurLI->reg),
+       E = MRI.reg_end(); I != E; ++I) {
+    MachineOperand &MO = I.getOperand();
+    if (MO.isUse() && MO.isUndef())
+      continue;
+    MachineInstr *MI = MO.getParent();
     if (MI->isDebugValue() || !UsingInstrs.insert(MI))
       continue;
     UseSlots.push_back(LIS.getInstructionIndex(MI).getDefIndex());
@@ -918,6 +922,14 @@
       MO.setReg(0);
       continue;
     }
+
+    // <undef> operands don't really read the register, so just assign them to
+    // the complement.
+    if (MO.isUse() && MO.isUndef()) {
+      MO.setReg(Edit.get(0)->reg);
+      continue;
+    }
+
     SlotIndex Idx = LIS.getInstructionIndex(MI);
     Idx = MO.isUse() ? Idx.getUseIndex() : Idx.getDefIndex();