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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.

llvm-svn: 64319
This commit is contained in:
Dan Gohman 2009-02-11 20:25:59 +00:00
parent 5ee2c02ac6
commit 298a2946f1
1 changed files with 0 additions and 11 deletions
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11
llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
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@ -899,12 +899,6 @@ namespace {
}; };
} // end anonymous namespace } // 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. /// CalcNodeSethiUllmanNumber - Compute Sethi Ullman number.
/// Smaller number is the higher priority. /// Smaller number is the higher priority.
static unsigned static unsigned
@ -986,11 +980,6 @@ namespace {
unsigned getNodePriority(const SUnit *SU) const { unsigned getNodePriority(const SUnit *SU) const {
assert(SU->NodeNum < SethiUllmanNumbers.size()); assert(SU->NodeNum < SethiUllmanNumbers.size());
unsigned Opc = SU->getNode() ? SU->getNode()->getOpcode() : 0; 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) if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg)
// CopyToReg should be close to its uses to facilitate coalescing and // CopyToReg should be close to its uses to facilitate coalescing and
// avoid spilling. // avoid spilling.