[gcc r13-1254] d: Construct indexes of ARRAY_TYPE using ARRAY_REF.

[gcc r13-1254] d: Construct indexes of ARRAY_TYPE using ARRAY_REF.

[Iain Buclaw]

https://gcc.gnu.org/g:8288cd635fa0bd75a8c5f25c7a90d4a7a4acec81

commit r13-1254-g8288cd635fa0bd75a8c5f25c7a90d4a7a4acec81
Author: Iain Buclaw <ibuclaw@gdcproject.org>
Date:   Fri Jun 24 19:48:55 2022 +0200

    d: Construct indexes of ARRAY_TYPE using ARRAY_REF.
    
    This is a small simplification over `((T *)&array)[index]', which also
    allows eliding an unneccesary marking of TREE_ADDRESSABLE when the array
    expression is a parameter or variable declaration.
    
    gcc/d/ChangeLog:
    
            * d-codegen.cc (build_array_index): Rename to...
            (build_pointer_index): ...this.
            * d-tree.h (build_array_index): Rename declaration to...
            (build_pointer_index): ...this.
            * expr.cc (ExprVisitor::visit (IndexExp *)): Construct indexes of
            ARRAY_TYPE using ARRAY_REF.
            (ExprVisitor::visit (SliceExp *)): Update.
            * intrinsics.cc (expand_intrinsic_bt): Update.

Diff:
---
 gcc/d/d-codegen.cc  |  2 +-
 gcc/d/d-tree.h      |  2 +-
 gcc/d/expr.cc       | 38 +++++++++++++++++++++++++++++++-------
 gcc/d/intrinsics.cc |  4 ++--
 4 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/gcc/d/d-codegen.cc b/gcc/d/d-codegen.cc
index 0e14654e56b..3a201149d74 100644
--- a/gcc/d/d-codegen.cc
+++ b/gcc/d/d-codegen.cc
@@ -1626,7 +1626,7 @@ build_deref (tree exp)
 /* Builds pointer offset expression PTR[INDEX].  */
 
 tree
-build_array_index (tree ptr, tree index)
+build_pointer_index (tree ptr, tree index)
 {
   if (error_operand_p (ptr) || error_operand_p (index))
     return error_mark_node;
diff --git a/gcc/d/d-tree.h b/gcc/d/d-tree.h
index 751746395e6..a6c38119458 100644
--- a/gcc/d/d-tree.h
+++ b/gcc/d/d-tree.h
@@ -578,7 +578,7 @@ extern tree imaginary_part (tree);
 extern tree complex_expr (tree, tree, tree);
 extern tree indirect_ref (tree, tree);
 extern tree build_deref (tree);
-extern tree build_array_index (tree, tree);
+extern tree build_pointer_index (tree, tree);
 extern tree build_offset_op (tree_code, tree, tree);
 extern tree build_offset (tree, tree);
 extern tree build_memref (tree, tree, tree);
diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index fba397bed35..bf750924594 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -1222,9 +1222,8 @@ public:
       }
     else
       {
-	/* Get the data pointer and length for static and dynamic arrays.  */
+	/* Get the array and length for static and dynamic arrays.  */
 	tree array = d_save_expr (build_expr (e->e1));
-	tree ptr = convert_expr (array, tb1, tb1->nextOf ()->pointerTo ());
 
 	tree length = NULL_TREE;
 	if (tb1->ty != TY::Tpointer)
@@ -1245,10 +1244,35 @@ public:
 	if (tb1->ty != TY::Tpointer)
 	  index = build_bounds_index_condition (e, index, length);
 
-	/* Index the .ptr.  */
-	ptr = void_okay_p (ptr);
-	this->result_ = indirect_ref (TREE_TYPE (TREE_TYPE (ptr)),
-				      build_array_index (ptr, index));
+	/* Convert vectors to their underlying array type.  */
+	if (VECTOR_TYPE_P (TREE_TYPE (array)))
+	  {
+	    tree array_type =
+	      build_array_type_nelts (TREE_TYPE (TREE_TYPE (array)),
+				      TYPE_VECTOR_SUBPARTS (TREE_TYPE (array)));
+	    d_mark_addressable (array);
+	    array = build1 (VIEW_CONVERT_EXPR, array_type, array);
+	  }
+
+	if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
+	  {
+	    /* Generate `array[index]'.  When the index is non-constant, we must
+	       mark the array as addressable because we'll need to do pointer
+	       arithmetic on its address.  */
+	    if (TREE_CODE (index) != INTEGER_CST)
+	      d_mark_addressable (array);
+
+	    this->result_ = build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (array)),
+				    array, index, NULL_TREE, NULL_TREE);
+	  }
+	else
+	  {
+	    /* Generate `array.ptr[index]'.  */
+	    tree ptr = convert_expr (array, tb1, tb1->nextOf ()->pointerTo ());
+	    ptr = void_okay_p (ptr);
+	    this->result_ = indirect_ref (TREE_TYPE (TREE_TYPE (ptr)),
+					  build_pointer_index (ptr, index));
+	  }
       }
   }
 
@@ -1347,7 +1371,7 @@ public:
     if (!integer_zerop (lwr_tree))
       {
 	tree ptrtype = TREE_TYPE (ptr);
-	ptr = build_array_index (void_okay_p (ptr), lwr_tree);
+	ptr = build_pointer_index (void_okay_p (ptr), lwr_tree);
 	ptr = build_nop (ptrtype, ptr);
       }
 
diff --git a/gcc/d/intrinsics.cc b/gcc/d/intrinsics.cc
index 4222b8a0290..0f96284473f 100644
--- a/gcc/d/intrinsics.cc
+++ b/gcc/d/intrinsics.cc
@@ -306,8 +306,8 @@ expand_intrinsic_bt (intrinsic_code intrinsic, tree callexp)
   tree bitsize = fold_convert (type, TYPE_SIZE (TREE_TYPE (ptr)));
 
   /* ptr[bitnum / bitsize]  */
-  ptr = build_array_index (ptr, fold_build2 (TRUNC_DIV_EXPR, type,
-					     bitnum, bitsize));
+  ptr = build_pointer_index (ptr, fold_build2 (TRUNC_DIV_EXPR, type,
+					       bitnum, bitsize));
   ptr = indirect_ref (type, ptr);
 
   /* mask = 1 << (bitnum % bitsize);  */