Lower zeroing array assignment to memset for allocatable arrays.

gcc/fortran/ChangeLog:
	* trans-expr.cc (gfc_trans_zero_assign): Handle allocatable arrays.

gcc/testsuite/ChangeLog:
	* gfortran.dg/array_memset_3.f90: New test.

Signed-off-by: Prathamesh Kulkarni <prathameshk@nvidia.com>

1 files changed, 21 insertions, 10 deletions

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index 3ff2485..fc23fb1 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -11499,18 +11499,24 @@ gfc_trans_zero_assign (gfc_expr * expr)
   type = TREE_TYPE (dest);
   if (POINTER_TYPE_P (type))
     type = TREE_TYPE (type);
-  if (!GFC_ARRAY_TYPE_P (type))
-    return NULL_TREE;
-
-  /* Determine the length of the array.  */
-  len = GFC_TYPE_ARRAY_SIZE (type);
-  if (!len || TREE_CODE (len) != INTEGER_CST)
+  if (GFC_ARRAY_TYPE_P (type))
+    {
+      /* Determine the length of the array.  */
+      len = GFC_TYPE_ARRAY_SIZE (type);
+      if (!len || TREE_CODE (len) != INTEGER_CST)
+	return NULL_TREE;
+    }
+  else if (GFC_DESCRIPTOR_TYPE_P (type)
+	  && gfc_is_simply_contiguous (expr, false, false))
+    {
+      if (POINTER_TYPE_P (TREE_TYPE (dest)))
+	dest = build_fold_indirect_ref_loc (input_location, dest);
+      len = gfc_conv_descriptor_size (dest, GFC_TYPE_ARRAY_RANK (type));
+      dest = gfc_conv_descriptor_data_get (dest);
+    }
+  else
     return NULL_TREE;
 
-  tmp = TYPE_SIZE_UNIT (gfc_get_element_type (type));
-  len = fold_build2_loc (input_location, MULT_EXPR, gfc_array_index_type, len,
-			 fold_convert (gfc_array_index_type, tmp));
-
   /* If we are zeroing a local array avoid taking its address by emitting
      a = {} instead.  */
   if (!POINTER_TYPE_P (TREE_TYPE (dest)))
@@ -11518,6 +11524,11 @@ gfc_trans_zero_assign (gfc_expr * expr)
 		       dest, build_constructor (TREE_TYPE (dest),
 					      NULL));
 
+  /* Multiply len by element size.  */
+  tmp = TYPE_SIZE_UNIT (gfc_get_element_type (type));
+  len = fold_build2_loc (input_location, MULT_EXPR, gfc_array_index_type,
+			 len, fold_convert (gfc_array_index_type, tmp));
+
   /* Convert arguments to the correct types.  */
   dest = fold_convert (pvoid_type_node, dest);
   len = fold_convert (size_type_node, len);