https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97840
Jan Hubicka <hubicka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2020-11-15
Status|UNCONFIRMED |NEW
CC| |hubicka at gcc dot gnu.org
--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Confirmed. Reproduces on aarch64 cross for me, not on x86-64 native.
Warning is on:
#1 0x0000000001343ad5 in maybe_warn_pass_by_reference (stmt=0x7ffff32ec558,
wlims=...) at ../../gcc/tree-ssa-uninit.c:530
530 tree argbase = maybe_warn_operand (ref, stmt, NULL_TREE, arg,
wlims);
(gdb) down
#0 maybe_warn_operand (ref=..., stmt=0x7ffff32ec558, lhs=0x0,
rhs=0x7ffff55b93f0, wlims=...) at ../../gcc/tree-ssa-uninit.c:434
434 warned = warning_at (location, OPT_Wmaybe_uninitialized,
(gdb) p debug_generic_stmt (rhs)
D.89878
std::filesystem::__cxx11::recursive_directory_iterator::pop (struct
recursive_directory_iterator * const this)
{
struct error_code ec;
struct allocator D.89878;
....
std::__cxx11::basic_string<char>::basic_string<> (&D.89879, iftmp.99_1,
&D.89878);
....
D.89878 ={v} {CLOBBER};
....
and is otherwise unused.
Function looks identical with -fno-ipa-modref.
std::__cxx11::basic_string<char>::basic_string<> is defined locally and the
last parameter (__a) is unused.
modref determines flags
parm 2 flags: direct noclobber noescape unused
That seems all OK to me, so it seems that somehow uninit pass gets more active
because of different alias info.
