[llvm-commits] [llvm] r158379 - in /llvm/trunk: include/llvm/CodeGen/ScheduleDAG.h lib/CodeGen/ScheduleDAG.cpp
Andrew Trick
atrick at apple.com
Tue Jun 12 19:39:00 PDT 2012
Author: atrick
Date: Tue Jun 12 21:39:00 2012
New Revision: 158379
URL: http://llvm.org/viewvc/llvm-project?rev=158379&view=rev
Log:
sched: Avoid trivially redundant DAG edges. Take the one with higher latency.
Modified:
llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h
llvm/trunk/lib/CodeGen/ScheduleDAG.cpp
Modified: llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h?rev=158379&r1=158378&r2=158379&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h (original)
+++ llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h Tue Jun 12 21:39:00 2012
@@ -117,8 +117,9 @@
}
}
- bool operator==(const SDep &Other) const {
- if (Dep != Other.Dep || Latency != Other.Latency) return false;
+ /// Return true if the specified SDep is equivalent except for latency.
+ bool overlaps(const SDep &Other) const {
+ if (Dep != Other.Dep) return false;
switch (Dep.getInt()) {
case Data:
case Anti:
@@ -133,6 +134,10 @@
llvm_unreachable("Invalid dependency kind!");
}
+ bool operator==(const SDep &Other) const {
+ return overlaps(Other) && Latency == Other.Latency;
+ }
+
bool operator!=(const SDep &Other) const {
return !operator==(Other);
}
Modified: llvm/trunk/lib/CodeGen/ScheduleDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ScheduleDAG.cpp?rev=158379&r1=158378&r2=158379&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ScheduleDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/ScheduleDAG.cpp Tue Jun 12 21:39:00 2012
@@ -64,10 +64,27 @@
/// specified node.
bool SUnit::addPred(const SDep &D) {
// If this node already has this depenence, don't add a redundant one.
- for (SmallVector<SDep, 4>::const_iterator I = Preds.begin(), E = Preds.end();
- I != E; ++I)
- if (*I == D)
+ for (SmallVector<SDep, 4>::iterator I = Preds.begin(), E = Preds.end();
+ I != E; ++I) {
+ if (I->overlaps(D)) {
+ // Extend the latency if needed. Equivalent to removePred(I) + addPred(D).
+ if (I->getLatency() < D.getLatency()) {
+ SUnit *PredSU = I->getSUnit();
+ // Find the corresponding successor in N.
+ SDep ForwardD = *I;
+ ForwardD.setSUnit(this);
+ for (SmallVector<SDep, 4>::iterator II = PredSU->Succs.begin(),
+ EE = PredSU->Succs.end(); II != EE; ++II) {
+ if (*II == ForwardD) {
+ II->setLatency(D.getLatency());
+ break;
+ }
+ }
+ I->setLatency(D.getLatency());
+ }
return false;
+ }
+ }
// Now add a corresponding succ to N.
SDep P = D;
P.setSUnit(this);
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