[pach, Fortran] Improve dependency checking

[Thomas Koenig <tkoenig at netcologne dot de>]

Hello world,

here's another installment of dependency checking improvements.

I debated a little with myself if extending gfc_ref_dimen_size really
was the right approach, but I didn't want to duplicate its code.

Regression-tested on trunk.  OK?

[If there isn't time to review this before tomorrow evening, I would
ask somebody to commit this for me].

	Thomas

2010-08-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/44235
	* array.c (gfc_ref_dimen_size):  Add end argument.
	If end is non-NULL, calculate it.
	(ref_size):  Adjust call to gfc_ref_dimen_size.
	(gfc_array_dimen_size):  Likewise.
	(gfc_array_res_shape):  Likewise.
	* gfortran.h:  Adjust prototype for gfc_ref_dimen_size.
	* resolve.c (resolve_array_ref):  For stride not equal to -1,
	fill in the lowest possible end.

2010-08-09  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/44235
	* dependency_32.f90:  New test.

Index: array.c
===================================================================
--- array.c	(Revision 162824)
+++ array.c	(Arbeitskopie)
@@ -1940,10 +1940,11 @@ spec_size (gfc_array_spec *as, mpz_t *result)
 }
 
 
-/* Get the number of elements in an array section.  */
+/* Get the number of elements in an array section. Optionally, also supply
+   the end value.  */
 
 gfc_try
-gfc_ref_dimen_size (gfc_array_ref *ar, int dimen, mpz_t *result)
+gfc_ref_dimen_size (gfc_array_ref *ar, int dimen, mpz_t *result, mpz_t *end)
 {
   mpz_t upper, lower, stride;
   gfc_try t;
@@ -2016,6 +2017,15 @@ gfc_try
 	mpz_set_ui (*result, 0);
       t = SUCCESS;
 
+      if (end)
+	{
+	  mpz_init (*end);
+
+	  mpz_sub_ui (*end, *result, 1UL);
+	  mpz_mul (*end, *end, stride);
+	  mpz_add (*end, *end, lower);
+	}
+
     cleanup:
       mpz_clear (upper);
       mpz_clear (lower);
@@ -2040,7 +2050,7 @@ ref_size (gfc_array_ref *ar, mpz_t *result)
 
   for (d = 0; d < ar->dimen; d++)
     {
-      if (gfc_ref_dimen_size (ar, d, &size) == FAILURE)
+      if (gfc_ref_dimen_size (ar, d, &size, NULL) == FAILURE)
 	{
 	  mpz_clear (*result);
 	  return FAILURE;
@@ -2086,7 +2096,7 @@ gfc_array_dimen_size (gfc_expr *array, int dimen,
 		if (ref->u.ar.dimen_type[i] != DIMEN_ELEMENT)
 		  dimen--;
 
-	      return gfc_ref_dimen_size (&ref->u.ar, i - 1, result);
+	      return gfc_ref_dimen_size (&ref->u.ar, i - 1, result, NULL);
 	    }
 	}
 
@@ -2222,7 +2232,7 @@ gfc_array_ref_shape (gfc_array_ref *ar, mpz_t *sha
 	{
 	  if (ar->dimen_type[i] != DIMEN_ELEMENT)
 	    {
-	      if (gfc_ref_dimen_size (ar, i, &shape[d]) == FAILURE)
+	      if (gfc_ref_dimen_size (ar, i, &shape[d], NULL) == FAILURE)
 		goto cleanup;
 	      d++;
 	    }
Index: gfortran.h
===================================================================
--- gfortran.h	(Revision 162824)
+++ gfortran.h	(Arbeitskopie)
@@ -2753,7 +2753,7 @@ gfc_try spec_size (gfc_array_spec *, mpz_t *);
 gfc_try spec_dimen_size (gfc_array_spec *, int, mpz_t *);
 int gfc_is_compile_time_shape (gfc_array_spec *);
 
-gfc_try gfc_ref_dimen_size (gfc_array_ref *, int dimen, mpz_t *);
+gfc_try gfc_ref_dimen_size (gfc_array_ref *, int dimen, mpz_t *, mpz_t *);
 
 
 /* interface.c -- FIXME: some of these should be in symbol.c */
Index: resolve.c
===================================================================
--- resolve.c	(Revision 162824)
+++ resolve.c	(Arbeitskopie)
@@ -4316,6 +4316,37 @@ resolve_array_ref (gfc_array_ref *ar)
 		       &ar->c_where[i], e->rank);
 	    return FAILURE;
 	  }
+
+      /* Fill in the upper bound, which may be lower than the
+	 specified one for something like a(2:10:5), which is
+	 identical to a(2:7:5).  Only relevant for non-zero strides.  */
+      if (ar->dimen_type[i] == DIMEN_RANGE
+	  && ar->stride[i] != NULL && ar->stride[i]->expr_type == EXPR_CONSTANT
+	  && mpz_cmp_si (ar->stride[i]->value.integer, 1L) != 0)
+	{
+	  mpz_t size, end;
+
+	  if (gfc_ref_dimen_size (ar, i, &size, &end) == SUCCESS)
+	    {
+	      if (ar->end[i] == NULL)
+		{
+		  ar->end[i] =
+		    gfc_get_constant_expr (BT_INTEGER, gfc_index_integer_kind,
+					   &ar->where);
+		  mpz_set (ar->end[i]->value.integer, end);
+		}
+	      else if (ar->end[i]->ts.type == BT_INTEGER
+		       && ar->end[i]->expr_type == EXPR_CONSTANT)
+		{
+		  mpz_set (ar->end[i]->value.integer, end);
+		}
+	      else
+		gcc_unreachable ();
+
+	      mpz_clear (size);
+	      mpz_clear (end);
+	    }
+	}
     }
 
   if (ar->type == AR_FULL && ar->as->rank == 0)
Index: simplify.c
===================================================================
--- simplify.c	(Revision 162824)
+++ simplify.c	(Arbeitskopie)
@@ -2807,7 +2807,7 @@ simplify_bound_dim (gfc_expr *array, gfc_expr *kin
     {
       if (upper)
 	{
-	  if (gfc_ref_dimen_size (&ref->u.ar, d-1, &result->value.integer)
+	  if (gfc_ref_dimen_size (&ref->u.ar, d-1, &result->value.integer, NULL)
 	      != SUCCESS)
 	    goto returnNull;
 	}

! { dg-do compile }
! { dg-options "-Warray-temporaries" }
! PR 44235
! No temporary should be created for this, as the upper bounds
! are effectively identical.
program main
  real a(10)
  a = 0.
  a(1:10:4) = a(1:9:4)
end program main