2011-04-08 Thomas Koenig <tkoenig@gcc.gnu.org>

	PR fortran/48448
	* gfortran.h (gfc_option_t):  Add warn_function_elimination and
	flag_frontend_optimize.
	* lang.opt (Wfunction-elimination):  Add.
	(ffrontend-optimize):  Add.
	* invoke.texi:  Add documentation for -Wfunction-elimination
	and -ffrontend-optimize.  Add -faggressive-function-elimination
	to list of code generation options.
	* frontend-passes.c (gfc_run_passes):  Run optimizations if
	flag_frontend_optimize is set.
	(warn_function_elimination):  New function.
	(cfe_expr_0):  Call it if requested to do so.
	* options.c (gfc_init_options):  Initiate warn_function_elimination
	and flag_frontend_optimize.
	(gfc_post_options):  Set flag_frontend_optimize if not specified
	by user, depending on the optimization level.
	(gfc_handle_option):  Handle -Wfunction-elimination and
	-ffrontend-optimize.

2011-04-08  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/48448
	* gfortran.dg/function_optimize_5.f90:  New test.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@172215 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 19 insertions, 1 deletions

diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c
index b6f6b4cd020..cabfd285586 100644
--- a/gcc/fortran/frontend-passes.c
+++ b/gcc/fortran/frontend-passes.c
@@ -62,7 +62,7 @@ gfc_namespace *current_ns;
 void
 gfc_run_passes (gfc_namespace *ns)
 {
-  if (optimize)
+  if (gfc_option.flag_frontend_optimize)
     {
       expr_size = 20;
       expr_array = XNEWVEC(gfc_expr **, expr_size);
@@ -283,6 +283,20 @@ create_var (gfc_expr * e)
   return result;
 }
 
+/* Warn about function elimination.  */
+
+static void
+warn_function_elimination (gfc_expr *e)
+{
+  if (e->expr_type != EXPR_FUNCTION)
+    return;
+  if (e->value.function.esym)
+    gfc_warning ("Removing call to function '%s' at %L",
+		 e->value.function.esym->name, &(e->where));
+  else if (e->value.function.isym)
+    gfc_warning ("Removing call to function '%s' at %L",
+		 e->value.function.isym->name, &(e->where));
+}
 /* Callback function for the code walker for doing common function
    elimination.  This builds up the list of functions in the expression
    and goes through them to detect duplicates, which it then replaces
@@ -315,6 +329,10 @@ cfe_expr_0 (gfc_expr **e, int *walk_subtrees,
 	    {
 	      if (newvar == NULL)
 		newvar = create_var (*(expr_array[i]));
+
+	      if (gfc_option.warn_function_elimination)
+		warn_function_elimination (*(expr_array[j]));
+
 	      gfc_free (*(expr_array[j]));
 	      *(expr_array[j]) = gfc_copy_expr (newvar);
 	    }