* trans-expr.c (gfc_trans_assignment_1): New subroutine to scalarize

	array assignments split out from gfc_trans_assignment.
	(gfc_trans_array_copy): New function to implement array to array
	copies via calls to __builtin_memcpy.
	(copyable_array_p): New helper function to identify an array of
	simple/POD types, that may be copied/assigned using memcpy.
	(gfc_trans_assignment): Use gfc_trans_array_copy to handle simple
	whole array assignments considered suitable by copyable_array_p.
	Invoke gfc_trans_assignment_1 to perform the fallback scalarization.

	* gfortran.dg/array_memcpy_1.f90: New test case.
	* gfortran.dg/array_memcpy_2.f90: Likewise.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@120503 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 206 insertions, 24 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index a6d222341a0..005d4b3965b 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,5 +1,17 @@
 2007-01-05  Roger Sayle  <roger@eyesopen.com>
 
+	* trans-expr.c (gfc_trans_assignment_1): New subroutine to scalarize
+	array assignments split out from gfc_trans_assignment.
+	(gfc_trans_array_copy): New function to implement array to array
+	copies via calls to __builtin_memcpy.
+	(copyable_array_p): New helper function to identify an array of
+	simple/POD types, that may be copied/assigned using memcpy.
+	(gfc_trans_assignment): Use gfc_trans_array_copy to handle simple
+	whole array assignments considered suitable by copyable_array_p.
+	Invoke gfc_trans_assignment_1 to perform the fallback scalarization.
+
+2007-01-05  Roger Sayle  <roger@eyesopen.com>
+
 	* trans-array.c (gfc_trans_array_constructor_value): Make the
 	static const "data" array as TREE_READONLY.
 	* trans-stmt.c (gfc_trans_character_select): Likewise.
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index e534aff7841..c6ebf3e8b31 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -3579,11 +3579,76 @@ gfc_trans_zero_assign (gfc_expr * expr)
   return fold_convert (void_type_node, tmp);
 }
 
-/* Translate an assignment.  Most of the code is concerned with
-   setting up the scalarizer.  */
+/* Try to efficiently translate dst(:) = src(:).  Return NULL if this
+   can't be done.  EXPR1 is the destination/lhs and EXPR2 is the
+   source/rhs, both are gfc_full_array_ref_p which have been checked for
+   dependencies.  */
 
-tree
-gfc_trans_assignment (gfc_expr * expr1, gfc_expr * expr2, bool init_flag)
+static tree
+gfc_trans_array_copy (gfc_expr * expr1, gfc_expr * expr2)
+{
+  tree dst, dlen, dtype;
+  tree src, slen, stype;
+  tree tmp, args;
+
+  dst = gfc_get_symbol_decl (expr1->symtree->n.sym);
+  src = gfc_get_symbol_decl (expr2->symtree->n.sym);
+
+  dtype = TREE_TYPE (dst);
+  if (POINTER_TYPE_P (dtype))
+    dtype = TREE_TYPE (dtype);
+  stype = TREE_TYPE (src);
+  if (POINTER_TYPE_P (stype))
+    stype = TREE_TYPE (stype);
+
+  if (!GFC_ARRAY_TYPE_P (dtype) || !GFC_ARRAY_TYPE_P (stype))
+    return NULL_TREE;
+
+  /* Determine the lengths of the arrays.  */
+  dlen = GFC_TYPE_ARRAY_SIZE (dtype);
+  if (!dlen || TREE_CODE (dlen) != INTEGER_CST)
+    return NULL_TREE;
+  dlen = fold_build2 (MULT_EXPR, gfc_array_index_type, dlen,
+		      TYPE_SIZE_UNIT (gfc_get_element_type (dtype)));
+
+  slen = GFC_TYPE_ARRAY_SIZE (stype);
+  if (!slen || TREE_CODE (slen) != INTEGER_CST)
+    return NULL_TREE;
+  slen = fold_build2 (MULT_EXPR, gfc_array_index_type, slen,
+		      TYPE_SIZE_UNIT (gfc_get_element_type (stype)));
+
+  /* Sanity check that they are the same.  This should always be
+     the case, as we should already have checked for conformance.  */
+  if (!tree_int_cst_equal (slen, dlen))
+    return NULL_TREE;
+
+  /* Convert arguments to the correct types.  */
+  if (!POINTER_TYPE_P (TREE_TYPE (dst)))
+    dst = gfc_build_addr_expr (pvoid_type_node, dst);
+  else
+    dst = fold_convert (pvoid_type_node, dst);
+
+  if (!POINTER_TYPE_P (TREE_TYPE (src)))
+    src = gfc_build_addr_expr (pvoid_type_node, src);
+  else
+    src = fold_convert (pvoid_type_node, src);
+
+  dlen = fold_convert (size_type_node, dlen);
+
+  /* Construct call to __builtin_memcpy.  */
+  args = build_tree_list (NULL_TREE, dlen);
+  args = tree_cons (NULL_TREE, src, args);
+  args = tree_cons (NULL_TREE, dst, args);
+  tmp = build_function_call_expr (built_in_decls[BUILT_IN_MEMCPY], args);
+  return fold_convert (void_type_node, tmp);
+}
+
+
+/* Subroutine of gfc_trans_assignment that actually scalarizes the
+   assignment.  EXPR1 is the destination/RHS and EXPR2 is the source/LHS.  */
+
+static tree
+gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr * expr2, bool init_flag)
 {
   gfc_se lse;
   gfc_se rse;
@@ -3596,26 +3661,6 @@ gfc_trans_assignment (gfc_expr * expr1, gfc_expr * expr2, bool init_flag)
   stmtblock_t body;
   bool l_is_temp;
 
-  /* Special case a single function returning an array.  */
-  if (expr2->expr_type == EXPR_FUNCTION && expr2->rank > 0)
-    {
-      tmp = gfc_trans_arrayfunc_assign (expr1, expr2);
-      if (tmp)
-	return tmp;
-    }
-
-  /* Special case assigning an array to zero.  */
-  if (expr1->expr_type == EXPR_VARIABLE
-      && expr1->rank > 0
-      && expr1->ref
-      && gfc_full_array_ref_p (expr1->ref)
-      && is_zero_initializer_p (expr2))
-    {
-      tmp = gfc_trans_zero_assign (expr1);
-      if (tmp)
-        return tmp;
-    }
-
   /* Assignment of the form lhs = rhs.  */
   gfc_start_block (&block);
 
@@ -3751,6 +3796,78 @@ gfc_trans_assignment (gfc_expr * expr1, gfc_expr * expr2, bool init_flag)
   return gfc_finish_block (&block);
 }
 
+
+/* Check whether EXPR, which is an EXPR_VARIABLE, is a copyable array.  */
+
+static bool
+copyable_array_p (gfc_expr * expr)
+{
+  /* First check it's an array.  */
+  if (expr->rank < 1 || !expr->ref)
+    return false;
+
+  /* Next check that it's of a simple enough type.  */
+  switch (expr->ts.type)
+    {
+    case BT_INTEGER:
+    case BT_REAL:
+    case BT_COMPLEX:
+    case BT_LOGICAL:
+      return true;
+
+    default:
+      break;
+    }
+
+  return false;
+}
+
+/* Translate an assignment.  */
+
+tree
+gfc_trans_assignment (gfc_expr * expr1, gfc_expr * expr2, bool init_flag)
+{
+  tree tmp;
+
+  /* Special case a single function returning an array.  */
+  if (expr2->expr_type == EXPR_FUNCTION && expr2->rank > 0)
+    {
+      tmp = gfc_trans_arrayfunc_assign (expr1, expr2);
+      if (tmp)
+	return tmp;
+    }
+
+  /* Special case assigning an array to zero.  */
+  if (expr1->expr_type == EXPR_VARIABLE
+      && expr1->rank > 0
+      && expr1->ref
+      && gfc_full_array_ref_p (expr1->ref)
+      && is_zero_initializer_p (expr2))
+    {
+      tmp = gfc_trans_zero_assign (expr1);
+      if (tmp)
+        return tmp;
+    }
+
+  /* Special case copying one array to another.  */
+  if (expr1->expr_type == EXPR_VARIABLE
+      && copyable_array_p (expr1)
+      && gfc_full_array_ref_p (expr1->ref)
+      && expr2->expr_type == EXPR_VARIABLE
+      && copyable_array_p (expr2)
+      && gfc_full_array_ref_p (expr2->ref)
+      && gfc_compare_types (&expr1->ts, &expr2->ts)
+      && !gfc_check_dependency (expr1, expr2, 0))
+    {
+      tmp = gfc_trans_array_copy (expr1, expr2);
+      if (tmp)
+        return tmp;
+    }
+
+  /* Fallback to the scalarizer to generate explicit loops.  */
+  return gfc_trans_assignment_1 (expr1, expr2, init_flag);
+}
+
 tree
 gfc_trans_init_assign (gfc_code * code)
 {
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 817846a9fb8..18909655fb5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-01-05  Roger Sayle  <roger@eyesopen.com>
+
+	* gfortran.dg/array_memcpy_1.f90: New test case.
+	* gfortran.dg/array_memcpy_2.f90: Likewise.
+
 2007-01-05  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/27826
diff --git a/gcc/testsuite/gfortran.dg/array_memcpy_1.f90 b/gcc/testsuite/gfortran.dg/array_memcpy_1.f90
new file mode 100644
index 00000000000..2d2f8f73073
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_memcpy_1.f90
@@ -0,0 +1,28 @@
+! { dg-do compile }
+! { dg-options "-O2 -fdump-tree-original" }
+subroutine testi(a,b)
+  integer :: a(20)
+  integer :: b(20)
+  a = b;
+end subroutine
+
+subroutine testr(a,b)
+  real :: a(20)
+  real :: b(20)
+  a = b;
+end subroutine
+
+subroutine testz(a,b)
+  complex :: a(20)
+  complex :: b(20)
+  a = b;
+end subroutine
+
+subroutine testl(a,b)
+  logical :: a(20)
+  logical :: b(20)
+  a = b;
+end subroutine
+
+! { dg-final { scan-tree-dump-times "memcpy" 4 "original" } }
+! { dg-final { cleanup-tree-dump "original" } }
diff --git a/gcc/testsuite/gfortran.dg/array_memcpy_2.f90 b/gcc/testsuite/gfortran.dg/array_memcpy_2.f90
new file mode 100644
index 00000000000..be8f00d1738
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_memcpy_2.f90
@@ -0,0 +1,20 @@
+! This checks that the "z = y" assignment is not considered copyable, as the
+! array is of a derived type containing allocatable components.  Hence, we
+! we should expand the scalarized loop, which contains *two* memcpy calls.
+! { dg-do compile }
+! { dg-options "-O2 -fdump-tree-original" }
+
+  type :: a
+    integer, allocatable :: i(:)
+  end type a
+
+  type :: b
+    type (a), allocatable :: at(:)
+  end type b
+
+  type(b) :: y(2), z(2)
+
+  z = y
+end
+! { dg-final { scan-tree-dump-times "memcpy" 2 "original" } }
+! { dg-final { cleanup-tree-dump "original" } }