[HLSL][Matrix] Add support for single subscript accessor

fixes #166206

- Add swizzle support if row index is constant
- Add test cases
- Add new AST type
- Add new LValue for Matrix Row Type
- TODO: Make the new LValue a dynamic index version of ExtVectorElt

Author: farzonl

clang/include/clang/AST/ComputeDependence.h

@@ -28,6 +28,7 @@ class ParenExpr;
 class UnaryOperator;
 class UnaryExprOrTypeTraitExpr;
 class ArraySubscriptExpr;
+class MatrixSingleSubscriptExpr;
 class MatrixSubscriptExpr;
 class CompoundLiteralExpr;
 class ImplicitCastExpr;
@@ -117,6 +118,7 @@ ExprDependence computeDependence(ParenExpr *E);
 ExprDependence computeDependence(UnaryOperator *E, const ASTContext &Ctx);
 ExprDependence computeDependence(UnaryExprOrTypeTraitExpr *E);
 ExprDependence computeDependence(ArraySubscriptExpr *E);
+ExprDependence computeDependence(MatrixSingleSubscriptExpr *E);
 ExprDependence computeDependence(MatrixSubscriptExpr *E);
 ExprDependence computeDependence(CompoundLiteralExpr *E);
 ExprDependence computeDependence(ImplicitCastExpr *E);

clang/include/clang/AST/Expr.h

@@ -2790,6 +2790,73 @@ class ArraySubscriptExpr : public Expr {
   }
 };
 
+/// MatrixSingleSubscriptExpr - Matrix single subscript expression for the
+/// MatrixType extension when you want to get\set a vector from a Matrix.
+class MatrixSingleSubscriptExpr : public Expr {
+  enum { BASE, ROW_IDX, END_EXPR };
+  Stmt *SubExprs[END_EXPR];
+
+public:
+  /// matrix[row]
+  ///
+  /// \param Base        The matrix expression.
+  /// \param RowIdx      The row index expression.
+  /// \param T           The type of the row (usually a vector type).
+  /// \param RBracketLoc Location of the closing ']'.
+  MatrixSingleSubscriptExpr(Expr *Base, Expr *RowIdx, QualType T,
+                            SourceLocation RBracketLoc)
+      : Expr(MatrixSingleSubscriptExprClass, T,
+             Base->getValueKind(), // lvalue/rvalue follows the matrix base
+             OK_MatrixComponent) { // or OK_Ordinary/OK_VectorComponent if you
+                                   // prefer
+    SubExprs[BASE] = Base;
+    SubExprs[ROW_IDX] = RowIdx;
+    ArrayOrMatrixSubscriptExprBits.RBracketLoc = RBracketLoc;
+    setDependence(computeDependence(this));
+  }
+
+  /// Create an empty matrix single-subscript expression.
+  explicit MatrixSingleSubscriptExpr(EmptyShell Shell)
+      : Expr(MatrixSingleSubscriptExprClass, Shell) {}
+
+  Expr *getBase() { return cast<Expr>(SubExprs[BASE]); }
+  const Expr *getBase() const { return cast<Expr>(SubExprs[BASE]); }
+  void setBase(Expr *E) { SubExprs[BASE] = E; }
+
+  Expr *getRowIdx() { return cast<Expr>(SubExprs[ROW_IDX]); }
+  const Expr *getRowIdx() const { return cast<Expr>(SubExprs[ROW_IDX]); }
+  void setRowIdx(Expr *E) { SubExprs[ROW_IDX] = E; }
+
+  SourceLocation getBeginLoc() const LLVM_READONLY {
+    return getBase()->getBeginLoc();
+  }
+
+  SourceLocation getEndLoc() const { return getRBracketLoc(); }
+
+  SourceLocation getExprLoc() const LLVM_READONLY {
+    return getBase()->getExprLoc();
+  }
+
+  SourceLocation getRBracketLoc() const {
+    return ArrayOrMatrixSubscriptExprBits.RBracketLoc;
+  }
+  void setRBracketLoc(SourceLocation L) {
+    ArrayOrMatrixSubscriptExprBits.RBracketLoc = L;
+  }
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == MatrixSingleSubscriptExprClass;
+  }
+
+  // Iterators
+  child_range children() {
+    return child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
+  }
+  const_child_range children() const {
+    return const_child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
+  }
+};
+
 /// MatrixSubscriptExpr - Matrix subscript expression for the MatrixType
 /// extension.
 /// MatrixSubscriptExpr can be either incomplete (only Base and RowIdx are set

clang/include/clang/AST/RecursiveASTVisitor.h

@@ -2894,6 +2894,7 @@ DEF_TRAVERSE_STMT(CXXMemberCallExpr, {})
 // over the children.
 DEF_TRAVERSE_STMT(AddrLabelExpr, {})
 DEF_TRAVERSE_STMT(ArraySubscriptExpr, {})
+DEF_TRAVERSE_STMT(MatrixSingleSubscriptExpr, {})
 DEF_TRAVERSE_STMT(MatrixSubscriptExpr, {})
 DEF_TRAVERSE_STMT(ArraySectionExpr, {})
 DEF_TRAVERSE_STMT(OMPArrayShapingExpr, {})

clang/include/clang/AST/Stmt.h

@@ -540,6 +540,7 @@ class alignas(void *) Stmt {
   class ArrayOrMatrixSubscriptExprBitfields {
     friend class ArraySubscriptExpr;
     friend class MatrixSubscriptExpr;
+    friend class MatrixSingleSubscriptExpr;
 
     LLVM_PREFERRED_TYPE(ExprBitfields)
     unsigned : NumExprBits;

clang/include/clang/Basic/StmtNodes.td

@@ -75,6 +75,7 @@ def UnaryOperator : StmtNode<Expr>;
 def OffsetOfExpr : StmtNode<Expr>;
 def UnaryExprOrTypeTraitExpr : StmtNode<Expr>;
 def ArraySubscriptExpr : StmtNode<Expr>;
+def MatrixSingleSubscriptExpr : StmtNode<Expr>;
 def MatrixSubscriptExpr : StmtNode<Expr>;
 def ArraySectionExpr : StmtNode<Expr>;
 def OMPIteratorExpr : StmtNode<Expr>;

clang/include/clang/Sema/Sema.h

@@ -7405,6 +7405,9 @@ class Sema final : public SemaBase {
   ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
                                              Expr *Idx, SourceLocation RLoc);
 
+  ExprResult CreateBuiltinMatrixSingleSubscriptExpr(Expr *Base, Expr *RowIdx,
+                                                    SourceLocation RBLoc);
+
   ExprResult CreateBuiltinMatrixSubscriptExpr(Expr *Base, Expr *RowIdx,
                                               Expr *ColumnIdx,
                                               SourceLocation RBLoc);

clang/lib/AST/ComputeDependence.cpp

@@ -115,6 +115,10 @@ ExprDependence clang::computeDependence(ArraySubscriptExpr *E) {
   return E->getLHS()->getDependence() | E->getRHS()->getDependence();
 }
 
+ExprDependence clang::computeDependence(MatrixSingleSubscriptExpr *E) {
+  return E->getBase()->getDependence() | E->getRowIdx()->getDependence();
+}
+
 ExprDependence clang::computeDependence(MatrixSubscriptExpr *E) {
   return E->getBase()->getDependence() | E->getRowIdx()->getDependence() |
          (E->getColumnIdx() ? E->getColumnIdx()->getDependence()

clang/lib/AST/Expr.cpp

@@ -3792,6 +3792,7 @@ bool Expr::HasSideEffects(const ASTContext &Ctx,
 
   case ParenExprClass:
   case ArraySubscriptExprClass:
+  case MatrixSingleSubscriptExprClass:
   case MatrixSubscriptExprClass:
   case ArraySectionExprClass:
   case OMPArrayShapingExprClass:

clang/lib/AST/ExprClassification.cpp

@@ -259,6 +259,9 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
     }
     return Cl::CL_LValue;
 
+  case Expr::MatrixSingleSubscriptExprClass:
+    return ClassifyInternal(Ctx, cast<MatrixSingleSubscriptExpr>(E)->getBase());
+
   // Subscripting matrix types behaves like member accesses.
   case Expr::MatrixSubscriptExprClass:
     return ClassifyInternal(Ctx, cast<MatrixSubscriptExpr>(E)->getBase());

clang/lib/AST/ExprConstant.cpp

@@ -20887,6 +20887,7 @@ static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
   case Expr::ImaginaryLiteralClass:
   case Expr::StringLiteralClass:
   case Expr::ArraySubscriptExprClass:
+  case Expr::MatrixSingleSubscriptExprClass:
   case Expr::MatrixSubscriptExprClass:
   case Expr::ArraySectionExprClass:
   case Expr::OMPArrayShapingExprClass: