Support HLSL matrix initializers

fixes #159434

In HLSL matrices are `matrix_type` in all respects except that they
support a constructor style syntax for initializing matrices. This
change adds a translation of vector constructor arguments into
initializer lists.

This supports the following HLSL syntax:
(1) HLSL matrices support constructor syntax
(2) HLSL matrices are expanded to constituate components in constructor

Author: farzonl

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -6543,9 +6543,9 @@ def warn_extern_init : Warning<"'extern' variable has an initializer">,
 def err_variable_object_no_init : Error<
   "variable-sized object may not be initialized">;
 def err_excess_initializers : Error<
-  "excess elements in %select{array|vector|scalar|union|struct}0 initializer">;
+  "excess elements in %select{array|vector|matrix|scalar|union|struct}0 initializer">;
 def ext_excess_initializers : ExtWarn<
-  "excess elements in %select{array|vector|scalar|union|struct}0 initializer">,
+  "excess elements in %select{array|vector|matrix|scalar|union|struct}0 initializer">,
   InGroup<ExcessInitializers>;
 def err_excess_initializers_for_sizeless_type : Error<
   "excess elements in initializer for indivisible sizeless type %0">;
@@ -11086,8 +11086,8 @@ def err_first_argument_to_cwsc_pdtor_call : Error<
 def err_second_argument_to_cwsc_not_pointer : Error<
   "second argument to __builtin_call_with_static_chain must be of pointer type">;
 
-def err_vector_incorrect_num_elements : Error<
-  "%select{too many|too few}0 elements in vector %select{initialization|operand}3 (expected %1 elements, have %2)">;
+def err_tensor_incorrect_num_elements : Error<
+  "%select{too many|too few}0 elements in %select{vector|matrix}1 %select{initialization|operand}4 (expected %2 elements, have %3)">;
 def err_altivec_empty_initializer : Error<"expected initializer">;
 
 def err_vector_incorrect_bit_count : Error<

clang/include/clang/Sema/Initialization.h

@@ -91,6 +91,10 @@ class alignas(8) InitializedEntity {
     /// or vector.
     EK_VectorElement,
 
+    /// The entity being initialized is an element of a matrix.
+    /// or matrix.
+    EK_MatrixElement,
+
     /// The entity being initialized is a field of block descriptor for
     /// the copied-in c++ object.
     EK_BlockElement,
@@ -205,8 +209,8 @@ class alignas(8) InitializedEntity {
     /// virtual base.
     llvm::PointerIntPair<const CXXBaseSpecifier *, 1> Base;
 
-    /// When Kind == EK_ArrayElement, EK_VectorElement, or
-    /// EK_ComplexElement, the index of the array or vector element being
+    /// When Kind == EK_ArrayElement, EK_VectorElement, or EK_MatrixElement,
+    /// or EK_ComplexElement, the index of the array or vector element being
     /// initialized.
     unsigned Index;
 
@@ -536,15 +540,15 @@ class alignas(8) InitializedEntity {
   /// element's index.
   unsigned getElementIndex() const {
     assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
-           getKind() == EK_ComplexElement);
+           getKind() == EK_MatrixElement || getKind() == EK_ComplexElement);
     return Index;
   }
 
   /// If this is already the initializer for an array or vector
   /// element, sets the element index.
   void setElementIndex(unsigned Index) {
     assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
-           getKind() == EK_ComplexElement);
+           getKind() == EK_MatrixElement || getKind() == EK_ComplexElement);
     this->Index = Index;
   }
 

clang/lib/Sema/CheckExprLifetime.cpp

@@ -154,6 +154,7 @@ getEntityLifetime(const InitializedEntity *Entity,
   case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
   case InitializedEntity::EK_LambdaCapture:
   case InitializedEntity::EK_VectorElement:
+  case clang::InitializedEntity::EK_MatrixElement:
   case InitializedEntity::EK_ComplexElement:
     return {nullptr, LK_FullExpression};