re PR fortran/51260 (PARAMETER array with constructor initializer: Compile-time…

re PR fortran/51260 (PARAMETER array with constructor initializer: Compile-time simplify single element access)

2018-04-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/51260
	* resolve.c (resolve_variable): Simplify cases where access to a
	parameter array results in a single constant.

2018-04-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/51260
	* gfortran.dg/parameter_array_element_3.f90: New test.

From-SVN: r259256

gcc/fortran/ChangeLog

+2018-04-09  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/51260
+	* resolve.c (resolve_variable): Simplify cases where access to a
+	parameter array results in a single constant.
+
 2018-04-02  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/85102

gcc/fortran/resolve.c

@@ -5577,6 +5577,16 @@ resolve_procedure:
   if (t && flag_coarray == GFC_FCOARRAY_LIB && gfc_is_coindexed (e))
     add_caf_get_intrinsic (e);
 
+  /* Simplify cases where access to a parameter array results in a
+     single constant.  Suppress errors since those will have been
+     issued before, as warnings.  */
+  if (e->rank == 0 && sym->as && sym->attr.flavor == FL_PARAMETER)
+    {
+      gfc_push_suppress_errors ();
+      gfc_simplify_expr (e, 1);
+      gfc_pop_suppress_errors ();
+    }
+
   return t;
 }
 

gcc/testsuite/ChangeLog

+2018-04-09  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/51260
+	* gfortran.dg/parameter_array_element_3.f90: New test.
+
 2018-04-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/85194

gcc/testsuite/gfortran.dg/parameter_array_element_3.f90

+! { dg-do compile }
+! PR 51260 - an unneeded parameter found its way into the
+! assembly code. Original test case by Tobias Burnus.
+module x
+contains
+  subroutine foo(i)
+    integer, intent(in) :: i
+  end subroutine foo
+end module x
+
+program main
+  use x
+  integer, parameter:: unneeded_parameter (10000)=(/(i,i=1,10000)/)
+  call foo(unneeded_parameter (1))
+  print *,unneeded_parameter (1)
+end program
+! { dg-final { scan-assembler-times "unneeded_parameter" 0 } }