re PR fortran/44265 (Link error with reference to parameter array in specification expression)

2016-12-09  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/44265
	* gfortran.h : Add fn_result_spec bitfield to gfc_symbol.
	* resolve.c (flag_fn_result_spec): New function.
	(resolve_fntype): Call it for character result lengths.
	* symbol.c (gfc_new_symbol): Set fn_result_spec to zero.
	* trans-decl.c (gfc_sym_mangled_identifier): Include the
	procedure name in the mangled name for symbols with the
	fn_result_spec bit set.
	(gfc_finish_var_decl): Mark the decls of these symbols
	appropriately for the case where the function is external.
	(gfc_get_symbol_decl): Mangle the name of these symbols.
	(gfc_create_module_variable): Allow them through the assert.
	(gfc_generate_function_code): Remove the assert before the
	initialization of sym->tlink because the frontend no longer
	uses this field.
	* trans-expr.c (gfc_map_intrinsic_function): Add a case to
	treat the LEN_TRIM intrinsic.
	(gfc_trans_string_copy): Deal with Wstringop-overflow warning
	that can occur with constant source lengths at -O3.

2016-12-09  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/44265
	* gfortran.dg/char_result_14.f90: New test.
	* gfortran.dg/char_result_15.f90: New test.

From-SVN: r243478

1 files changed, 21 insertions, 3 deletions

diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 78bff87..8cb0f1c 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -4116,6 +4116,16 @@ gfc_map_intrinsic_function (gfc_expr *expr, gfc_interface_mapping *mapping)
       new_expr = gfc_copy_expr (arg1->ts.u.cl->length);
       break;
 
+    case GFC_ISYM_LEN_TRIM:
+      new_expr = gfc_copy_expr (arg1);
+      gfc_apply_interface_mapping_to_expr (mapping, new_expr);
+
+      if (!new_expr)
+	return false;
+
+      gfc_replace_expr (arg1, new_expr);
+      return true;
+
     case GFC_ISYM_SIZE:
       if (!sym->as || sym->as->rank == 0)
 	return false;
@@ -6484,10 +6494,18 @@ gfc_trans_string_copy (stmtblock_t * block, tree dlength, tree dest,
 			      builtin_decl_explicit (BUILT_IN_MEMMOVE),
 			      3, dest, src, slen);
 
+  /* Wstringop-overflow appears at -O3 even though this warning is not
+     explicitly available in fortran nor can it be switched off. If the
+     source length is a constant, its negative appears as a very large
+     postive number and triggers the warning in BUILTIN_MEMSET. Fixing
+     the result of the MINUS_EXPR suppresses this spurious warning.  */
+  tmp = fold_build2_loc (input_location, MINUS_EXPR,
+			 TREE_TYPE(dlen), dlen, slen);
+  if (slength && TREE_CONSTANT (slength))
+    tmp = gfc_evaluate_now (tmp, block);
+
   tmp4 = fold_build_pointer_plus_loc (input_location, dest, slen);
-  tmp4 = fill_with_spaces (tmp4, chartype,
-			   fold_build2_loc (input_location, MINUS_EXPR,
-					    TREE_TYPE(dlen), dlen, slen));
+  tmp4 = fill_with_spaces (tmp4, chartype, tmp);
 
   gfc_init_block (&tempblock);
   gfc_add_expr_to_block (&tempblock, tmp3);