Mark the x86 machine model as incomplete. PR17367.

Ideally, the machinel model is added at the time the instructions are
defined. But many instructions in X86InstrSSE.td still need a model.

Without this workaround the scheduler asserts because x86 already has
itinerary classes for these instructions, indicating they should be
modeled by the scheduler. Since we use the new machine model for other
instructions, it expects a new machine model for these too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191391 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCSchedule.h

@@ -174,6 +174,8 @@ public:
   unsigned MispredictPenalty;
   static const unsigned DefaultMispredictPenalty = 10;
 
+  bool CompleteModel;
+
 private:
   unsigned ProcID;
   const MCProcResourceDesc *ProcResourceTable;
@@ -194,6 +196,7 @@ public:
                   LoadLatency(DefaultLoadLatency),
                   HighLatency(DefaultHighLatency),
                   MispredictPenalty(DefaultMispredictPenalty),
+                  CompleteModel(true),
                   ProcID(0), ProcResourceTable(0), SchedClassTable(0),
                   NumProcResourceKinds(0), NumSchedClasses(0),
                   InstrItineraries(0) {
@@ -203,19 +206,23 @@ public:
 
   // Table-gen driven ctor.
   MCSchedModel(unsigned iw, int mbs, unsigned ll, unsigned hl,
-               unsigned mp, unsigned pi, const MCProcResourceDesc *pr,
+               unsigned mp, bool cm, unsigned pi, const MCProcResourceDesc *pr,
                const MCSchedClassDesc *sc, unsigned npr, unsigned nsc,
                const InstrItinerary *ii):
     IssueWidth(iw), MicroOpBufferSize(mbs), LoadLatency(ll), HighLatency(hl),
-    MispredictPenalty(mp), ProcID(pi), ProcResourceTable(pr),
-    SchedClassTable(sc), NumProcResourceKinds(npr), NumSchedClasses(nsc),
-    InstrItineraries(ii) {}
+    MispredictPenalty(mp), CompleteModel(cm), ProcID(pi),
+    ProcResourceTable(pr), SchedClassTable(sc), NumProcResourceKinds(npr),
+    NumSchedClasses(nsc), InstrItineraries(ii) {}
 
   unsigned getProcessorID() const { return ProcID; }
 
   /// Does this machine model include instruction-level scheduling.
   bool hasInstrSchedModel() const { return SchedClassTable; }
 
+  /// Return true if this machine model data for all instructions with a
+  /// scheduling class (itinerary class or SchedRW list).
+  bool isComplete() const { return CompleteModel; }
+
   unsigned getNumProcResourceKinds() const {
     return NumProcResourceKinds;
   }

include/llvm/Target/TargetSchedule.td

@@ -86,6 +86,15 @@ class SchedMachineModel {
   // Per-cycle resources tables.
   ProcessorItineraries Itineraries = NoItineraries;
 
+  // Subtargets that define a model for only a subset of instructions
+  // that have a scheduling class (itinerary class or SchedRW list)
+  // and may actually be generated for that subtarget must clear this
+  // bit. Otherwise, the scheduler considers an unmodelled opcode to
+  // be an error. This should only be set during initial bringup,
+  // or there will be no way to catch simple errors in the model
+  // resulting from changes to the instruction definitions.
+  bit CompleteModel = 1;
+
   bit NoModel = 0; // Special tag to indicate missing machine model.
 }
 

lib/CodeGen/TargetSchedule.cpp

@@ -210,7 +210,8 @@ unsigned TargetSchedModel::computeOperandLatency(
   // unit latency (defaultDefLatency may be too conservative).
 #ifndef NDEBUG
   if (SCDesc->isValid() && !DefMI->getOperand(DefOperIdx).isImplicit()
-      && !DefMI->getDesc().OpInfo[DefOperIdx].isOptionalDef()) {
+      && !DefMI->getDesc().OpInfo[DefOperIdx].isOptionalDef()
+      && SchedModel.isComplete()) {
     std::string Err;
     raw_string_ostream ss(Err);
     ss << "DefIdx " << DefIdx << " exceeds machine model writes for "

lib/Target/X86/X86SchedHaswell.td

@@ -19,6 +19,10 @@ def HaswellModel : SchedMachineModel {
   let MicroOpBufferSize = 192; // Based on the reorder buffer.
   let LoadLatency = 4;
   let MispredictPenalty = 16;
+
+  // FIXME: SSE4 and AVX are unimplemented. This flag is set to allow
+  // the scheduler to assign a default model to unrecognized opcodes.
+  let CompleteModel = 0;
 }
 
 let SchedModel = HaswellModel in {

lib/Target/X86/X86SchedSandyBridge.td

@@ -20,6 +20,10 @@ def SandyBridgeModel : SchedMachineModel {
   let MicroOpBufferSize = 168; // Based on the reorder buffer.
   let LoadLatency = 4;
   let MispredictPenalty = 16;
+
+  // FIXME: SSE4 and AVX are unimplemented. This flag is set to allow
+  // the scheduler to assign a default model to unrecognized opcodes.
+  let CompleteModel = 0;
 }
 
 let SchedModel = SandyBridgeModel in {

utils/TableGen/SubtargetEmitter.cpp

@@ -1198,6 +1198,11 @@ void SubtargetEmitter::EmitProcessorModels(raw_ostream &OS) {
     EmitProcessorProp(OS, PI->ModelDef, "LoadLatency", ',');
     EmitProcessorProp(OS, PI->ModelDef, "HighLatency", ',');
     EmitProcessorProp(OS, PI->ModelDef, "MispredictPenalty", ',');
+
+    OS << "  " << (bool)(PI->ModelDef ?
+                         PI->ModelDef->getValueAsBit("CompleteModel") : 0)
+       << ", // " << "CompleteModel\n";
+
     OS << "  " << PI->Index << ", // Processor ID\n";
     if (PI->hasInstrSchedModel())
       OS << "  " << PI->ModelName << "ProcResources" << ",\n"