X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FTargetSchedule.cpp;h=64ee9d1c464eac92aba19c80e6ec1b8f7d40b429;hb=fe532525cc4912ec0d1b4e91fa0396122dd087b3;hp=ca3b0e0b1173d63e2f605c483938c590def2195d;hpb=8d4abb2446f80986ad5136bbec30c5da18cd6f4b;p=oota-llvm.git diff --git a/lib/CodeGen/TargetSchedule.cpp b/lib/CodeGen/TargetSchedule.cpp index ca3b0e0b117..64ee9d1c464 100644 --- a/lib/CodeGen/TargetSchedule.cpp +++ b/lib/CodeGen/TargetSchedule.cpp @@ -13,12 +13,12 @@ //===----------------------------------------------------------------------===// #include "llvm/CodeGen/TargetSchedule.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/raw_ostream.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Target/TargetSubtargetInfo.h" -#include "llvm/Support/CommandLine.h" -#include "llvm/Support/raw_ostream.h" using namespace llvm; @@ -93,33 +93,10 @@ unsigned TargetSchedModel::getNumMicroOps(const MachineInstr *MI, // effectively means infinite latency. Since users of the TargetSchedule API // don't know how to handle this, we convert it to a very large latency that is // easy to distinguish when debugging the DAG but won't induce overflow. -static unsigned convertLatency(int Cycles) { +static unsigned capLatency(int Cycles) { return Cycles >= 0 ? Cycles : 1000; } -/// If we can determine the operand latency from the def only, without machine -/// model or itinerary lookup, do so. Otherwise return -1. -int TargetSchedModel::getDefLatency(const MachineInstr *DefMI, - bool FindMin) const { - - // Return a latency based on the itinerary properties and defining instruction - // if possible. Some common subtargets don't require per-operand latency, - // especially for minimum latencies. - if (FindMin) { - // If MinLatency is invalid, then use the itinerary for MinLatency. If no - // itinerary exists either, then use single cycle latency. - if (SchedModel.MinLatency < 0 && !hasInstrItineraries()) { - return 1; - } - return SchedModel.MinLatency; - } - else if (!hasInstrSchedModel() && !hasInstrItineraries()) { - return TII->defaultDefLatency(&SchedModel, DefMI); - } - // ...operand lookup required - return -1; -} - /// Return the MCSchedClassDesc for this instruction. Some SchedClasses require /// evaluation of predicates that depend on instruction operands or flags. const MCSchedClassDesc *TargetSchedModel:: @@ -128,6 +105,8 @@ resolveSchedClass(const MachineInstr *MI) const { // Get the definition's scheduling class descriptor from this machine model. unsigned SchedClass = MI->getDesc().getSchedClass(); const MCSchedClassDesc *SCDesc = SchedModel.getSchedClassDesc(SchedClass); + if (!SCDesc->isValid()) + return SCDesc; #ifndef NDEBUG unsigned NIter = 0; @@ -175,18 +154,16 @@ static unsigned findUseIdx(const MachineInstr *MI, unsigned UseOperIdx) { // Top-level API for clients that know the operand indices. unsigned TargetSchedModel::computeOperandLatency( const MachineInstr *DefMI, unsigned DefOperIdx, - const MachineInstr *UseMI, unsigned UseOperIdx, - bool FindMin) const { + const MachineInstr *UseMI, unsigned UseOperIdx) const { - int DefLatency = getDefLatency(DefMI, FindMin); - if (DefLatency >= 0) - return DefLatency; + if (!hasInstrSchedModel() && !hasInstrItineraries()) + return TII->defaultDefLatency(&SchedModel, DefMI); if (hasInstrItineraries()) { int OperLatency = 0; if (UseMI) { - OperLatency = - TII->getOperandLatency(&InstrItins, DefMI, DefOperIdx, UseMI, UseOperIdx); + OperLatency = TII->getOperandLatency(&InstrItins, DefMI, DefOperIdx, + UseMI, UseOperIdx); } else { unsigned DefClass = DefMI->getDesc().getSchedClass(); @@ -203,13 +180,11 @@ unsigned TargetSchedModel::computeOperandLatency( // hook to allow subtargets to specialize latency. This hook is only // applicable to the InstrItins model. InstrSchedModel should model all // special cases without TII hooks. - if (!FindMin) - InstrLatency = std::max(InstrLatency, - TII->defaultDefLatency(&SchedModel, DefMI)); + InstrLatency = std::max(InstrLatency, + TII->defaultDefLatency(&SchedModel, DefMI)); return InstrLatency; } - assert(!FindMin && hasInstrSchedModel() && - "Expected a SchedModel for this cpu"); + // hasInstrSchedModel() const MCSchedClassDesc *SCDesc = resolveSchedClass(DefMI); unsigned DefIdx = findDefIdx(DefMI, DefOperIdx); if (DefIdx < SCDesc->NumWriteLatencyEntries) { @@ -217,7 +192,7 @@ unsigned TargetSchedModel::computeOperandLatency( const MCWriteLatencyEntry *WLEntry = STI->getWriteLatencyEntry(SCDesc, DefIdx); unsigned WriteID = WLEntry->WriteResourceID; - unsigned Latency = convertLatency(WLEntry->Cycles); + unsigned Latency = capLatency(WLEntry->Cycles); if (!UseMI) return Latency; @@ -226,7 +201,10 @@ unsigned TargetSchedModel::computeOperandLatency( if (UseDesc->NumReadAdvanceEntries == 0) return Latency; unsigned UseIdx = findUseIdx(UseMI, UseOperIdx); - return Latency - STI->getReadAdvanceCycles(UseDesc, UseIdx, WriteID); + int Advance = STI->getReadAdvanceCycles(UseDesc, UseIdx, WriteID); + if (Advance > 0 && (unsigned)Advance > Latency) // unsigned wrap + return 0; + return Latency - Advance; } // If DefIdx does not exist in the model (e.g. implicit defs), then return // unit latency (defaultDefLatency may be too conservative). @@ -240,7 +218,10 @@ unsigned TargetSchedModel::computeOperandLatency( report_fatal_error(ss.str()); } #endif - return DefMI->isTransient() ? 0 : 1; + // FIXME: Automatically giving all implicit defs defaultDefLatency is + // undesirable. We should only do it for defs that are known to the MC + // desc like flags. Truly implicit defs should get 1 cycle latency. + return DefMI->isTransient() ? 0 : TII->defaultDefLatency(&SchedModel, DefMI); } unsigned TargetSchedModel::computeInstrLatency(const MachineInstr *MI) const { @@ -258,7 +239,7 @@ unsigned TargetSchedModel::computeInstrLatency(const MachineInstr *MI) const { // Lookup the definition's write latency in SubtargetInfo. const MCWriteLatencyEntry *WLEntry = STI->getWriteLatencyEntry(SCDesc, DefIdx); - Latency = std::max(Latency, convertLatency(WLEntry->Cycles)); + Latency = std::max(Latency, capLatency(WLEntry->Cycles)); } return Latency; } @@ -269,13 +250,10 @@ unsigned TargetSchedModel::computeInstrLatency(const MachineInstr *MI) const { unsigned TargetSchedModel:: computeOutputLatency(const MachineInstr *DefMI, unsigned DefOperIdx, const MachineInstr *DepMI) const { - // MinLatency == -1 is for in-order processors that always have unit - // MinLatency. MinLatency > 0 is for in-order processors with varying min - // latencies, but since this is not a RAW dep, we always use unit latency. - if (SchedModel.MinLatency != 0) + if (SchedModel.MicroOpBufferSize <= 1) return 1; - // MinLatency == 0 indicates an out-of-order processor that can dispatch + // MicroOpBufferSize > 1 indicates an out-of-order processor that can dispatch // WAW dependencies in the same cycle. // Treat predication as a data dependency for out-of-order cpus. In-order @@ -297,7 +275,7 @@ computeOutputLatency(const MachineInstr *DefMI, unsigned DefOperIdx, if (SCDesc->isValid()) { for (const MCWriteProcResEntry *PRI = STI->getWriteProcResBegin(SCDesc), *PRE = STI->getWriteProcResEnd(SCDesc); PRI != PRE; ++PRI) { - if (!SchedModel.getProcResource(PRI->ProcResourceIdx)->IsBuffered) + if (!SchedModel.getProcResource(PRI->ProcResourceIdx)->BufferSize) return 1; } }