re PR fortran/85111 (ICE in min_max_choose, at fortran/simplify.c:4884 (and others))

2017-03-30  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/85111
	* array.c (gfc_resolve_character_array_constructor): Early
	exit for zero-size arrays.
	* simplify.c (simplify_transformation_to_array): Exit early
	if the result size is zero.
	(simplify_minmaxloc_to_array): Likewise.

2017-03-30  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/85111
	* gfortran.dg/zero_sized_10.f90: New test.

From-SVN: r258973

gcc/fortran/array.c

@@ -2003,6 +2003,20 @@ gfc_resolve_character_array_constructor (gfc_expr *expr)
 
 got_charlen:
 
+  /* Early exit for zero size arrays. */
+  if (expr->shape)
+    {
+      mpz_t size;
+      HOST_WIDE_INT arraysize;
+
+      gfc_array_size (expr, &size);
+      arraysize = mpz_get_ui (size);
+      mpz_clear (size);
+
+      if (arraysize == 0)
+	return true;
+    }
+
   found_length = -1;
 
   if (expr->ts.u.cl->length == NULL)

gcc/fortran/simplify.c

@@ -627,7 +627,7 @@ simplify_transformation_to_array (gfc_expr *result, gfc_expr *array, gfc_expr *d
       n += 1;
     }
 
-  done = false;
+  done = resultsize <= 0;
   base = arrayvec;
   dest = resultvec;
   while (!done)
@@ -5304,7 +5304,7 @@ simplify_minmaxloc_to_array (gfc_expr *result, gfc_expr *array,
       n += 1;
     }
 
-  done = false;
+  done = resultsize <= 0;
   base = arrayvec;
   dest = resultvec;
   while (!done)

gcc/testsuite/gfortran.dg/zero_sized_10.f90

+! { dg-do compile }
+! { PR 85111 - this used to ICE. }
+! Original test case by Gernhard Steinmetz.
+program p
+   integer, parameter :: a(2,0) = reshape([1,2,3,4], shape(a))
+   character, parameter :: ac(2,0) = reshape(['a','b','c','d'], shape(ac))
+   integer, parameter :: b(2) = maxloc(a, dim=1) ! { dg-error "Different shape" }
+   integer, parameter :: c(2) = minloc(a, dim=1) ! { dg-error "Different shape" }
+   character, parameter :: d(2) = maxval(ac, dim=1) ! { dg-error "Different shape" }
+ end program p