If two instructions are both two-address code, favors (schedule closer to
terminator) the one that has a CopyToReg use. This fixes
2006-05-11-InstrSched.ll with -new-cc-modeling-scheme.
llvm-svn: 42453
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index 92dbb7c..ff751a9 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -1144,10 +1144,26 @@
}
+/// 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 @@
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 @@
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