https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116221
--- Comment #11 from anlauf at gcc dot gnu.org ---
(In reply to Sam James from comment #9)
> A handful more:
> ```
> In function ‘gfc_restore_backend_locus’,
> inlined from ‘gfc_trans_if_1’ at
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> trans-stmt.cc:1485:31:
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> trans.cc:2323:39: warning: ‘saved_loc.lb’ may be used uninitialized
> [-Wmaybe-uninitialized]
> 2323 | gfc_current_backend_file = loc->lb->file;
> | ^
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> trans-stmt.cc: In function ‘gfc_trans_if_1’:
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> trans-stmt.cc:1464:9: note: ‘saved_loc.lb’ was declared here
> 1464 | locus saved_loc;
> | ^
This one is a false-positive. The code in question is:
if (code->expr1->where.lb)
{
gfc_save_backend_locus (&saved_loc);
gfc_set_backend_locus (&code->expr1->where);
}
gfc_conv_expr_val (&if_se, code->expr1);
if (code->expr1->where.lb)
gfc_restore_backend_locus (&saved_loc);
Maybe LTO does not understand that gfc_conv_expr_val (my guess) does not have
a side-effect that changes the condition (code->expr1->where.lb != NULL).
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> parse.cc: In function ‘parse_contained’:
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> parse.cc:6578:15: warning: ‘sym’ may be used uninitialized
> [-Wmaybe-uninitialized]
> 6578 | if (!sym->attr.pure)
> | ^
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> parse.cc:6507:15: note: ‘sym’ was declared here
> 6507 | gfc_symbol *sym;
> | ^
That could be solved by initializing sym.
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> match.cc: In function ‘gfc_match_call’:
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> match.cc:5132:33: warning: ‘select_st’ may be used uninitialized
> [-Wmaybe-uninitialized]
> 5132 | select_sym = select_st->n.sym;
> | ^
> /var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/fortran/
> match.cc:5124:20: note: ‘select_st’ declared here
> 5124 | gfc_symtree *select_st;
> | ^
That's again because gfc_get_ha_sym_tree is complicated and can be fixed
by initializing select_st.
