Teach if-converter to be more careful with predicating instructions that would
take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113570 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp
index ea93dd5..da0b056 100644
--- a/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -32,9 +32,9 @@
ScheduleDAGInstrs::ScheduleDAGInstrs(MachineFunction &mf,
const MachineLoopInfo &mli,
const MachineDominatorTree &mdt)
- : ScheduleDAG(mf), MLI(mli), MDT(mdt), Defs(TRI->getNumRegs()),
- Uses(TRI->getNumRegs()), LoopRegs(MLI, MDT) {
- MFI = mf.getFrameInfo();
+ : ScheduleDAG(mf), MLI(mli), MDT(mdt), MFI(mf.getFrameInfo()),
+ InstrItins(mf.getTarget().getInstrItineraryData()),
+ Defs(TRI->getNumRegs()), Uses(TRI->getNumRegs()), LoopRegs(MLI, MDT) {
DbgValueVec.clear();
}
@@ -498,23 +498,22 @@
}
void ScheduleDAGInstrs::ComputeLatency(SUnit *SU) {
- const InstrItineraryData &InstrItins = TM.getInstrItineraryData();
-
// Compute the latency for the node.
- SU->Latency =
- InstrItins.getStageLatency(SU->getInstr()->getDesc().getSchedClass());
+ if (!InstrItins || InstrItins->isEmpty()) {
+ SU->Latency = 1;
- // Simplistic target-independent heuristic: assume that loads take
- // extra time.
- if (InstrItins.isEmpty())
+ // Simplistic target-independent heuristic: assume that loads take
+ // extra time.
if (SU->getInstr()->getDesc().mayLoad())
SU->Latency += 2;
+ } else
+ SU->Latency =
+ InstrItins->getStageLatency(SU->getInstr()->getDesc().getSchedClass());
}
void ScheduleDAGInstrs::ComputeOperandLatency(SUnit *Def, SUnit *Use,
SDep& dep) const {
- const InstrItineraryData &InstrItins = TM.getInstrItineraryData();
- if (InstrItins.isEmpty())
+ if (!InstrItins || InstrItins->isEmpty())
return;
// For a data dependency with a known register...
@@ -528,8 +527,8 @@
MachineInstr *DefMI = Def->getInstr();
int DefIdx = DefMI->findRegisterDefOperandIdx(Reg);
if (DefIdx != -1) {
- int DefCycle = InstrItins.getOperandCycle(DefMI->getDesc().getSchedClass(),
- DefIdx);
+ int DefCycle = InstrItins->getOperandCycle(DefMI->getDesc().getSchedClass(),
+ DefIdx);
if (DefCycle >= 0) {
MachineInstr *UseMI = Use->getInstr();
const unsigned UseClass = UseMI->getDesc().getSchedClass();
@@ -544,7 +543,7 @@
if (MOReg != Reg)
continue;
- int UseCycle = InstrItins.getOperandCycle(UseClass, i);
+ int UseCycle = InstrItins->getOperandCycle(UseClass, i);
if (UseCycle >= 0)
Latency = std::max(Latency, DefCycle - UseCycle + 1);
}