[llvm-commits] [llvm] r101183 - /llvm/trunk/lib/CodeGen/MachineLICM.cpp

[Evan Cheng]

Author: evancheng
Date: Tue Apr 13 17:13:34 2010
New Revision: 101183

URL: http://llvm.org/viewvc/llvm-project?rev=101183&view=rev
Log:
Fast path implicit_def check.

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

Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=101183&r1=101182&r2=101183&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Tue Apr 13 17:13:34 2010
@@ -300,7 +300,7 @@
            "Not expecting virtual register!");
 
     if (!MO.isDef()) {
-      if (PhysRegDefs[Reg])
+      if (Reg && PhysRegDefs[Reg])
         // If it's using a non-loop-invariant register, then it's obviously not
         // safe to hoist.
         HasNonInvariantUse = true;
@@ -406,7 +406,7 @@
       MachineInstr *MI = Candidates[i].MI;
       for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) {
         const MachineOperand &MO = MI->getOperand(j);
-        if (!MO.isReg() || MO.isDef())
+        if (!MO.isReg() || MO.isDef() || !MO.getReg())
           continue;
         if (PhysRegDefs[MO.getReg()]) {
           // If it's using a non-loop-invariant register, then it's obviously
@@ -502,6 +502,9 @@
 /// candidate for LICM. e.g. If the instruction is a call, then it's obviously
 /// not safe to hoist it.
 bool MachineLICM::IsLICMCandidate(MachineInstr &I) {
+  if (I.isImplicitDef())
+    return false;
+
   const TargetInstrDesc &TID = I.getDesc();
   
   // Ignore stuff that we obviously can't hoist.
@@ -620,9 +623,6 @@
 /// IsProfitableToHoist - Return true if it is potentially profitable to hoist
 /// the given loop invariant.
 bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) {
-  if (MI.isImplicitDef())
-    return false;
-
   // FIXME: For now, only hoist re-materilizable instructions. LICM will
   // increase register pressure. We want to make sure it doesn't increase
   // spilling.