Avoid unnecessary declaration

Author: arsenm

llvm/test/TableGen/RegClassByHwMode.td

@@ -6,7 +6,6 @@
 
 include "llvm/Target/Target.td"
 
-
 // INSTRINFO: #if defined(GET_INSTRINFO_MC_DESC) || defined(GET_INSTRINFO_CTOR_DTOR)
 // INSTRINFO-NEXT: namespace {
 // INSTRINFO-NEXT: enum RegClassByHwModeUses : uint16_t {
@@ -24,6 +23,33 @@ include "llvm/Target/Target.td"
 // INSTRINFO: { YRegs_EvenIfRequired, 0|(1<<MCOI::LookupRegClassByHwMode), MCOI::OPERAND_REGISTER, 0 }, { XRegs_EvenIfRequired, 0|(1<<MCOI::LookupRegClassByHwMode), MCOI::OPERAND_REGISTER, 0 },
 
 
+// INSTRINFO: extern const int16_t MyTargetRegClassByHwModeTables[4][3] = {
+// INSTRINFO-NEXT:  { // DefaultMode
+// INSTRINFO-NEXT:    MyTarget::PtrRegs32RegClassID,
+// INSTRINFO-NEXT:    MyTarget::XRegsRegClassID,
+// INSTRINFO-NEXT:    MyTarget::YRegsRegClassID,
+// INSTRINFO-NEXT:  },
+// INSTRINFO-NEXT:  { // EvenMode
+// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:    MyTarget::XRegs_EvenRegClassID,
+// INSTRINFO-NEXT:    MyTarget::YRegs_EvenRegClassID,
+// INSTRINFO-NEXT:  },
+// INSTRINFO-NEXT:  { // OddMode
+// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:    MyTarget::XRegs_OddRegClassID,
+// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:  },
+// INSTRINFO-NEXT:  { // Ptr64
+// INSTRINFO-NEXT:    MyTarget::PtrRegs64RegClassID,
+// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:    -1, // Missing mode entry
+// INSTRINFO-NEXT:  },
+// INSTRINFO-NEXT: };
+
+// INSTRINFO: static inline void InitMyTargetMCInstrInfo(
+// INSTRINFO-NEXT: II->InitMCInstrInfo(MyTargetDescs.Insts, MyTargetInstrNameIndices, MyTargetInstrNameData, nullptr, nullptr, 321, &MyTargetRegClassByHwModeTables[0][0], 3);
+
+
 
 // ASMMATCHER: enum MatchClassKind {
 // ASMMATCHER:   MCK_LAST_TOKEN = OptionalMatchClass,

llvm/utils/TableGen/InstrInfoEmitter.cpp

@@ -1008,11 +1008,6 @@ void InstrInfoEmitter::run(raw_ostream &OS) {
   ArrayRef<const Record *> RegClassByHwMode = Target.getAllRegClassByHwMode();
   unsigned NumClassesByHwMode = RegClassByHwMode.size();
 
-  if (NumClassesByHwMode != 0) {
-    OS << "extern const int16_t " << TargetName << "RegClassByHwModeTables["
-       << NumModes << "][" << NumClassesByHwMode << "];\n";
-  }
-
   OS << "extern const unsigned " << TargetName << "InstrNameIndices[] = {";
   Num = 0;
   for (const CodeGenInstruction *Inst : NumberedInstructions) {
@@ -1072,7 +1067,7 @@ void InstrInfoEmitter::run(raw_ostream &OS) {
   Timer.startTimer("Emit initialization routine");
 
   if (NumClassesByHwMode != 0) {
-    OS << "const int16_t " << TargetName << "RegClassByHwModeTables["
+    OS << "extern const int16_t " << TargetName << "RegClassByHwModeTables["
        << NumModes << "][" << NumClassesByHwMode << "] = {\n";
 
     for (unsigned M = 0; M < NumModes; ++M) {