Merge commit d2353ae00c3b from llvm git (by Argyrios Kyrtzidis):

  [utils/TableGen/X86CompressEVEXTablesEmitter.cpp] Make sure the tablegen output for the `checkPredicate` function is deterministic (#84533)

  The output for the `checkPredicate` function was depending on a
  `std::map` iteration that was non-deterministic from run to run, because
  the keys were pointer values.

  Make a change so that the keys are `StringRef`s so the ordering is
  stable.

This avoids non-determinism in llvm-tblgen output, which could cause
differences in the generated X86GenCompressEVEXTables.inc file. Although
these differences are not influencing the meaning of the generated code,
they still change a few bytes in libllvm. This in turn influences all
the binaries linked with libllvm, such as clang, ld.lld, etc.

Reported by:	cperciva
MFC after:	3 days

contrib/llvm-project/llvm/utils/TableGen/X86CompressEVEXTablesEmitter.cpp

@@ -46,7 +46,7 @@ class X86CompressEVEXTablesEmitter {
 
   typedef std::pair<const CodeGenInstruction *, const CodeGenInstruction *>
       Entry;
-  typedef std::map<const Record *, std::vector<const CodeGenInstruction *>>
+  typedef std::map<StringRef, std::vector<const CodeGenInstruction *>>
       PredicateInstMap;
 
   std::vector<Entry> Table;
@@ -89,7 +89,7 @@ void X86CompressEVEXTablesEmitter::printCheckPredicate(
   for (const auto &[Key, Val] : PredicateInsts) {
     for (const auto &Inst : Val)
       OS << "  case X86::" << Inst->TheDef->getName() << ":\n";
-    OS << "    return " << Key->getValueAsString("CondString") << ";\n";
+    OS << "    return " << Key << ";\n";
   }
 
   OS << "  }\n";
@@ -226,7 +226,7 @@ void X86CompressEVEXTablesEmitter::run(raw_ostream &OS) {
              Name == "HasAVXIFMA";
     });
     if(It!= Predicates.end())
-      PredicateInsts[*It].push_back(NewInst);
+      PredicateInsts[(*It)->getValueAsString("CondString")].push_back(NewInst);
   }
 
   printTable(Table, OS);