[LLVM][TableGen] Speed up sorting of intrinsics

Speed up sorting of intrinsics by using the TargetPrefix to only
discriminate beteween target dependent vs target independent intrinsics
where target independent ones need to be sorted before target dependent
ones. When comaring two target dependent intrinsics, the Name already
includes llvm.<TargetPrefix> as a suffix, so no need to needlessly
compare it separately.

Author: jurahul

llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp

@@ -49,14 +49,21 @@ CodeGenIntrinsicTable::CodeGenIntrinsicTable(const RecordKeeper &RC) {
   for (const Record *Def : Defs)
     Intrinsics.emplace_back(CodeGenIntrinsic(Def, Ctx));
 
-  // To ensure deterministic sorted order when duplicates are present, use
-  // record ID as a tie-breaker similar to sortAndReportDuplicates in Utils.cpp.
   llvm::sort(Intrinsics,
              [](const CodeGenIntrinsic &LHS, const CodeGenIntrinsic &RHS) {
+               // Order target independent intrinsics before target dependent
+               // ones.
+               bool LHSHasTarget = !LHS.TargetPrefix.empty();
+               bool RHSHasTarget = !RHS.TargetPrefix.empty();
+
+               // To ensure deterministic sorted order when duplicates are
+               // present, use record ID as a tie-breaker similar to
+               // sortAndReportDuplicates in Utils.cpp.
                unsigned LhsID = LHS.TheDef->getID();
                unsigned RhsID = RHS.TheDef->getID();
-               return std::tie(LHS.TargetPrefix, LHS.Name, LhsID) <
-                      std::tie(RHS.TargetPrefix, RHS.Name, RhsID);
+
+               return std::tie(LHSHasTarget, LHS.Name, LhsID) <
+                      std::tie(RHSHasTarget, RHS.Name, RhsID);
              });
 
   Targets.push_back({"", 0, 0});