Hello world,
the attached patch fixes PR 51338. I chose a different approach
from what Bud did in the PR, because I rather wanted to fix the
specific code path when two NULL expressions were handled to
gfc_dep_compare_expr where determining the right answer is
straightforward rather than possibly introducing a (future?) logic
error.
Regression-tested. OK for trunk?
Thomas
2011-11-29 Thomas Koenig <[email protected]>
PR fortran/51338
* dependency.c (are_identical_variables): Handle case where
end fields of substring references are NULL.
2011-11-29 Thomas Koenig <[email protected]>
PR fortran/51338
* gfortran.dg/assumed_charlen_substring_1.f90: New test.
Index: dependency.c
===================================================================
--- dependency.c (Revision 181745)
+++ dependency.c (Arbeitskopie)
@@ -173,9 +173,18 @@ are_identical_variables (gfc_expr *e1, gfc_expr *e
break;
case REF_SUBSTRING:
- if (gfc_dep_compare_expr (r1->u.ss.start, r2->u.ss.start) != 0
- || gfc_dep_compare_expr (r1->u.ss.end, r2->u.ss.end) != 0)
+ if (gfc_dep_compare_expr (r1->u.ss.start, r2->u.ss.start) != 0)
return false;
+
+ /* This can only happen for assumed-length character arguments.
+ If both are NULL, the end length compares equal, because we
+ are looking at the same variable. */
+ if (r1->u.ss.end == NULL && r2->u.ss.end == NULL)
+ break;
+
+ if (gfc_dep_compare_expr (r1->u.ss.end, r2->u.ss.end) != 0)
+ return false;
+
break;
default:
! { dg-do compile }
! { dg-options "-O -fdump-tree-original" }
! PR 51338 - this used to ICE.
! Original test case by Bud Davis.
subroutine foo(a,b)
character(len=*) :: a
if (a(1:) /= a(1:)) call do_not_use
end subroutine foo
! { dg-final { scan-tree-dump-times "do_not_use" 0 "original" } }
! { dg-final { cleanup-tree-dump "original" } }
