2012-07-17  Tobias Burnus  <burnus@net-b.de>

	PR fortran/53985
	* decl.c (gfc_verify_c_interop_param): Make warning conditional
	on -Wc-binding-type works and improve the wording.

2012-07-17  Tobias Burnus  <burnus@net-b.de>

	PR fortran/53985
	* gfortran.dg/bind_c_usage_26.f90: New.
	* gfortran.dg/bind_c_procs.f03: Add dg-options "-Wc-binding-type".
	* gfortran.dg/bind_c_usage_13.f03: Ditto.
	* gfortran.dg/bind_c_usage_18.f90: Ditto.
	* gfortran.dg/interop_params.f03: Ditto.

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index c3644b6..c6ba43e 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -1027,8 +1032,8 @@ gfc_verify_c_interop_param (gfc_symbol *sym)
 			   "because it is polymorphic",
 			   sym->name, &(sym->declared_at),
 			   sym->ns->proc_name->name);
-	      else
-		gfc_warning ("Variable '%s' at %L is a parameter to the "
+	      else if (gfc_option.warn_c_binding_type)
+		gfc_warning ("Variable '%s' at %L is a dummy argument of the "
 			     "BIND(C) procedure '%s' but may not be C "
 			     "interoperable",
 			     sym->name, &(sym->declared_at),
--- /dev/null	2012-07-17 07:28:04.995717470 +0200
+++ gcc/gcc/testsuite/gfortran.dg/bind_c_usage_26.f90	2012-07-17 09:05:56.000000000 +0200
@@ -0,0 +1,14 @@
+! { dg-do compile }
+!
+! PR fortran/53985
+!
+! Check that the (default) -Wno-c-binding-type works
+! and no warning is printed.
+!
+! With -Wc-binding-type, one gets:
+!  Warning: Variable 'x' at (1) is a dummy argument to the BIND(C) procedure
+!           'test' but may not be C interoperable )
+!
+subroutine test(x) bind(C)
+  integer :: x
+end subroutine test
diff --git a/gcc/testsuite/gfortran.dg/bind_c_procs.f03 b/gcc/testsuite/gfortran.dg/bind_c_procs.f03
index eaf0672..3bb6ea3 100644
--- a/gcc/testsuite/gfortran.dg/bind_c_procs.f03
+++ b/gcc/testsuite/gfortran.dg/bind_c_procs.f03
@@ -1,4 +1,5 @@
 ! { dg-do compile }
+! { dg-options "-Wc-binding-type" }
 module bind_c_procs
   use, intrinsic :: iso_c_binding, only: c_int
 
diff --git a/gcc/testsuite/gfortran.dg/bind_c_usage_13.f03 b/gcc/testsuite/gfortran.dg/bind_c_usage_13.f03
index d89963d..b8c2261 100644
--- a/gcc/testsuite/gfortran.dg/bind_c_usage_13.f03
+++ b/gcc/testsuite/gfortran.dg/bind_c_usage_13.f03
@@ -1,5 +1,5 @@
 ! { dg-do compile }
-! { dg-options "-fdump-tree-original" }
+! { dg-options "-fdump-tree-original -Wc-binding-type" }
 !
 ! PR fortran/34079
 ! Character bind(c) arguments shall not pass the length as additional argument
diff --git a/gcc/testsuite/gfortran.dg/bind_c_usage_18.f90 b/gcc/testsuite/gfortran.dg/bind_c_usage_18.f90
index 2bce215..ede9f60 100644
--- a/gcc/testsuite/gfortran.dg/bind_c_usage_18.f90
+++ b/gcc/testsuite/gfortran.dg/bind_c_usage_18.f90
@@ -1,4 +1,5 @@
 ! { dg-do compile }
+! { dg-options "-Wc-binding-type" }
 !
 ! PR fortran/38160
 !
diff --git a/gcc/testsuite/gfortran.dg/interop_params.f03 b/gcc/testsuite/gfortran.dg/interop_params.f03
index ea3dada..6eafba0 100644
--- a/gcc/testsuite/gfortran.dg/interop_params.f03
+++ b/gcc/testsuite/gfortran.dg/interop_params.f03
@@ -1,4 +1,5 @@
 ! { dg-do compile }
+! { dg-options "-Wc-binding-type" }
 module interop_params
 use, intrinsic :: iso_c_binding