[llvm-commits] [llvm] r64319 - /llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp

[Dan Gohman]

Author: djg
Date: Wed Feb 11 14:25:59 2009
New Revision: 64319

URL: http://llvm.org/viewvc/llvm-project?rev=64319&view=rev
Log:
Delete the heuristic for non-livein CopyFromReg nodes. Non-liveinness
is determined by whether the node has a Flag operand. However, if the
node does have a Flag operand, it will be glued to its register's
def, so the heuristic would end up spuriously applying to whatever
node is the def.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp?rev=64319&r1=64318&r2=64319&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp Wed Feb 11 14:25:59 2009
@@ -899,12 +899,6 @@
   };
 }  // end anonymous namespace
 
-static inline bool isCopyFromLiveIn(const SUnit *SU) {
-  SDNode *N = SU->getNode();
-  return N && N->getOpcode() == ISD::CopyFromReg &&
-    N->getOperand(N->getNumOperands()-1).getValueType() != MVT::Flag;
-}
-
 /// CalcNodeSethiUllmanNumber - Compute Sethi Ullman number.
 /// Smaller number is the higher priority.
 static unsigned
@@ -986,11 +980,6 @@
     unsigned getNodePriority(const SUnit *SU) const {
       assert(SU->NodeNum < SethiUllmanNumbers.size());
       unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0;
-      if (Opc == ISD::CopyFromReg && !isCopyFromLiveIn(SU))
-        // CopyFromReg should be close to its def because it restricts
-        // allocation choices. But if it is a livein then perhaps we want it
-        // closer to its uses so it can be coalesced.
-        return 0xffff;
       if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
         // CopyToReg should be close to its uses to facilitate coalescing and
         // avoid spilling.