[clang] Remove source range from CXXOperatorCallExpr (llvm#147028)

This patch stops storing a source range in `CXXOperatorCallExpr` and
keeps only the begin location.

This change allows us to retain the optimization llvm#141058 when switching
to 64-bit source locations.

Performance results:

https://llvm-compile-time-tracker.com/compare.php?from=0588e8188c647460b641b09467fe6b13a8d510d5&to=5958f83476a8b8ba97936f262396d3ff98fb1662&stat=instructions:u

Author: hokein

clang/include/clang/AST/ExprCXX.h

@@ -84,7 +84,7 @@ class CXXOperatorCallExpr final : public CallExpr {
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 
-  SourceRange Range;
+  SourceLocation BeginLoc;
 
   // CXXOperatorCallExpr has some trailing objects belonging
   // to CallExpr. See CallExpr for the details.
@@ -158,9 +158,9 @@ class CXXOperatorCallExpr final : public CallExpr {
                : getOperatorLoc();
   }
 
-  SourceLocation getBeginLoc() const { return Range.getBegin(); }
-  SourceLocation getEndLoc() const { return Range.getEnd(); }
-  SourceRange getSourceRange() const { return Range; }
+  SourceLocation getBeginLoc() const { return BeginLoc; }
+  SourceLocation getEndLoc() const { return getSourceRangeImpl().getEnd(); }
+  SourceRange getSourceRange() const { return getSourceRangeImpl(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == CXXOperatorCallExprClass;

clang/lib/AST/ExprCXX.cpp

@@ -600,7 +600,7 @@ CXXOperatorCallExpr::CXXOperatorCallExpr(OverloadedOperatorKind OpKind,
   assert(
       (CXXOperatorCallExprBits.OperatorKind == static_cast<unsigned>(OpKind)) &&
       "OperatorKind overflow!");
-  Range = getSourceRangeImpl();
+  BeginLoc = getSourceRangeImpl().getBegin();
 }
 
 CXXOperatorCallExpr::CXXOperatorCallExpr(unsigned NumArgs, bool HasFPFeatures,

clang/lib/Serialization/ASTReaderStmt.cpp

@@ -1733,7 +1733,7 @@ void ASTStmtReader::VisitMSDependentExistsStmt(MSDependentExistsStmt *S) {
 void ASTStmtReader::VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
   VisitCallExpr(E);
   E->CXXOperatorCallExprBits.OperatorKind = Record.readInt();
-  E->Range = Record.readSourceRange();
+  E->BeginLoc = Record.readSourceLocation();
 }
 
 void ASTStmtReader::VisitCXXRewrittenBinaryOperator(

clang/lib/Serialization/ASTWriterDecl.cpp

@@ -2935,7 +2935,6 @@ void ASTWriter::WriteDeclAbbrevs() {
   // CXXOperatorCallExpr
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Operator Kind
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Source Location
   CXXOperatorCallExprAbbrev = Stream.EmitAbbrev(std::move(Abv));
 
   // Abbreviation for EXPR_CXX_MEMBER_CALL

clang/lib/Serialization/ASTWriterStmt.cpp

@@ -1702,7 +1702,7 @@ void ASTStmtWriter::VisitMSDependentExistsStmt(MSDependentExistsStmt *S) {
 void ASTStmtWriter::VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
   VisitCallExpr(E);
   Record.push_back(E->getOperator());
-  Record.AddSourceRange(E->Range);
+  Record.AddSourceLocation(E->BeginLoc);
 
   if (!E->hasStoredFPFeatures() && !static_cast<bool>(E->getADLCallKind()))
     AbbrevToUse = Writer.getCXXOperatorCallExprAbbrev();