Use clamp, update test accordingly.

Author: nvjle

llvm/test/TableGen/generic-tables-instruction.td

@@ -18,14 +18,12 @@ def Arch : Target { let InstructionSet = ArchInstrInfo; }
 // A contiguous primary (Instruction) key should get a direct lookup instead of
 // binary search.
 // CHECK: const MyInstr *getCustomEncodingHelper(unsigned Opcode) {
-// CHECK:   if ((Opcode < B) ||
-// CHECK:       (Opcode > D))
-// CHECK:     return nullptr;
+// CHECK: if ((unsigned)Opcode != std::clamp((unsigned)Opcode, (unsigned)B, (unsigned)D))
+// CHECK:   return nullptr;
 // CHECK:   auto Table = ArrayRef(InstrTable);
 // CHECK:   size_t Idx = Opcode - B;
 // CHECK:   return &Table[Idx];
 
-
 class MyInstr<int op> : Instruction {
   let OutOperandList = (outs);
   let InOperandList = (ins);
@@ -56,8 +54,7 @@ def InstrTable : GenericTable {
 //
 // Verify contiguous check for SearchIndex.
 // const MyInfoEntry *getTable2ByValue(uint8_t Value) {
-// CHECK:   if ((Value < 0xB) ||
-// CHECK:      (Value > 0xD))
+// CHECK:   if ((uint8_t)Value != std::clamp((uint8_t)Value, (uint8_t)0xB, (uint8_t)0xD))
 // CHECK:    return nullptr;
 // CHECK:  auto Table = ArrayRef(Index);
 // CHECK:  size_t Idx = Value - 0xB;

llvm/test/TableGen/generic-tables.td

@@ -113,8 +113,7 @@ def lookupBTableByNameAndFlag : SearchIndex {
 // CHECK: const CEntry *lookupCEntry(StringRef Name, unsigned Kind);
 // CHECK-LABEL: GET_CTable_IMPL
 // CHECK: const CEntry *lookupCEntryByEncoding(uint16_t Encoding) {
-// CHECK:   if ((Encoding < 0xA) ||
-// CHECK:       (Encoding > 0xF))
+// CHECK:   if ((uint16_t)Encoding != std::clamp((uint16_t)Encoding, (uint16_t)0xA, (uint16_t)0xF))
 // CHECK:     return nullptr;
 
 // CHECK: const CEntry *lookupCEntry(StringRef Name, unsigned Kind) {

llvm/utils/TableGen/SearchableTableEmitter.cpp

@@ -211,6 +211,7 @@ class SearchableTableEmitter {
 // known, return that numeric value.
 int64_t SearchableTableEmitter::getNumericKey(const SearchIndex &Index,
                                               const Record *Rec) {
+  assert(Index.Fields.size() == 1);
   const GenericField &Field = Index.Fields[0];
 
   // To be consistent with compareBy and primaryRepresentation elsewhere,
@@ -399,11 +400,11 @@ void SearchableTableEmitter::emitLookupFunction(const GenericTable &Table,
         Index.Loc, Field, IndexRows[0]->getValueInit(Field.Name));
     std::string LastRepr = primaryRepresentation(
         Index.Loc, Field, IndexRows.back()->getValueInit(Field.Name));
-    if (getNumericKey(Index, IndexRows[0]) == 0)
-      OS << "  if (";
-    else
-      OS << "  if ((" << Field.Name << " < " << FirstRepr << ") ||\n";
-    OS << "      (" << Field.Name << " > " << LastRepr << "))\n";
+    std::string TS =
+        '(' + searchableFieldType(Table, Index, Field, TypeInStaticStruct) +
+        ')';
+    OS << "  if (" << TS << Field.Name << " != std::clamp(" << TS << Field.Name
+       << ", " << TS << FirstRepr << ", " << TS << LastRepr << "))\n";
     OS << "    return nullptr;\n\n";
 
     if (IsContiguous && !Index.EarlyOut) {