https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91424
Bug ID: 91424
Summary: Extend warnings about DO loops
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: tkoenig at gcc dot gnu.org
Target Milestone: ---
Currently, there are two problems with the warnings about DO loop
indices accessing arrays with out of bounds errors:
- They are not given for contained procedures
- They are given twice for DO loops inside blocks
$ cat do_subscript_3.f90
! { dg-do compile }
! Check that only one warning is issued inside blocks, and that
! warnings are also issued for contained subroutines.
program main
real :: a(5)
block
integer :: j
do j=0, 5 ! { dg-warning "out of bounds" }
a(j) = 2. ! { dg-warning "out of bounds" }
end do
end block
call x
contains
subroutine x
integer :: i
do i=1,6 ! { dg-warning "out of bounds" }
a(i) = 2. ! { dg-warning "out of bounds" }
end do
end subroutine x
end program main
$ ~/Gcc/9-bin/gcc/f951 -quiet do_subscript_3.f90
do_subscript_3.f90:10:9:
9 | do j=0, 5 ! { dg-warning "out of bounds" }
| 2
10 | a(j) = 2. ! { dg-warning "out of bounds" }
| 1
Warning: Array reference at (1) out of bounds (0 < 1) in loop beginning at (2)
do_subscript_3.f90:10:9:
9 | do j=0, 5 ! { dg-warning "out of bounds" }
| 2
10 | a(j) = 2. ! { dg-warning "out of bounds" }
| 1
Warning: Array reference at (1) out of bounds (0 < 1) in loop beginning at (2)
Here's a patch:
Index: frontend-passes.c
===================================================================
--- frontend-passes.c (revision 273855)
+++ frontend-passes.c (working copy)
@@ -2556,6 +2556,12 @@
if (in_assoc_list)
return 0;
+ /* We already warned about this. */
+ if (v->do_not_warn)
+ return 0;
+
+ v->do_not_warn = 1;
+
for (ref = v->ref; ref; ref = ref->next)
{
if (ref->type == REF_ARRAY && ref->u.ar.type == AR_ELEMENT)
@@ -2761,6 +2767,12 @@
doloop_warn (gfc_namespace *ns)
{
gfc_code_walker (&ns->code, doloop_code, do_function, NULL);
+
+ for (ns = ns->contained; ns; ns = ns->sibling)
+ {
+ if (ns->code == NULL || ns->code->op != EXEC_BLOCK)
+ doloop_warn (ns);
+ }
}
/* This selction deals with inlining calls to MATMUL. */
