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If two instructions are both two-address code, favors (schedule closer to

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terminator) the one that has a CopyToReg use. This fixes
2006-05-11-InstrSched.ll with -new-cc-modeling-scheme.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42453 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2007-09-28 22:32:30 +00:00
parent 6745458195
commit 22a529990b
3 changed files with 27 additions and 10 deletions
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23
lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
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@@ -1144,10 +1144,26 @@ bool BURegReductionPriorityQueue<SF>::canClobber(SUnit *SU, SUnit *Op) {
}
/// hasCopyToRegUse - Return true if SU has a value successor that is a
/// CopyToReg node.
static bool hasCopyToRegUse(SUnit *SU) {
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
if (I->isCtrl) continue;
SUnit *SuccSU = I->Dep;
if (SuccSU->Node && SuccSU->Node->getOpcode() == ISD::CopyToReg)
return true;
}
return false;
}
/// AddPseudoTwoAddrDeps - If two nodes share an operand and one of them uses
/// it as a def&use operand. Add a pseudo control edge from it to the other
/// node (if it won't create a cycle) so the two-address one will be scheduled
/// first (lower in the schedule).
/// first (lower in the schedule). If both nodes are two-address, favor the
/// one that has a CopyToReg use (more likely to be a loop induction update).
/// If both are two-address, but one is commutable while the other is not
/// commutable, favor the one that's not commutable.
template<class SF>
void BURegReductionPriorityQueue<SF>::AddPseudoTwoAddrDeps() {
for (unsigned i = 0, e = SUnits->size(); i != e; ++i) {
@@ -1156,7 +1172,7 @@ void BURegReductionPriorityQueue<SF>::AddPseudoTwoAddrDeps() {
continue;
SDNode *Node = SU->Node;
if (!Node || !Node->isTargetOpcode())
if (!Node || !Node->isTargetOpcode() || SU->FlaggedNodes.size() > 0)
continue;
unsigned Opc = Node->getTargetOpcode();
@@ -1173,12 +1189,13 @@ void BURegReductionPriorityQueue<SF>::AddPseudoTwoAddrDeps() {
SUnit *SuccSU = I->Dep;
// Don't constraint nodes with implicit defs. It can create cycles
// plus it may increase register pressures.
if (SuccSU == SU || SuccSU->hasImplicitDefs)
if (SuccSU == SU || SuccSU->hasPhysRegDefs)
continue;
// Be conservative. Ignore if nodes aren't at the same depth.
if (SuccSU->Depth != SU->Depth)
continue;
if ((!canClobber(SuccSU, DUSU) ||
(hasCopyToRegUse(SU) && !hasCopyToRegUse(SuccSU)) ||
(!SU->isCommutable && SuccSU->isCommutable)) &&
!isReachable(SuccSU, SU)) {
DOUT << "Adding an edge from SU # " << SU->NodeNum