https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94905
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |msebor at gcc dot gnu.org
Known to fail| |11.2.1
Known to work| |12.0
Keywords| |needs-bisection
Last reconfirmed|2020-09-03 00:00:00 |2022-1-21
Summary|[10/11/12 Regression] Bogus |[10/11 Regression] Bogus
|warning |warning
|-Werror=maybe-uninitialized |-Werror=maybe-uninitialized
--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
The diagnostic is gone with GCC 12 as we there pattern-recognize a memcpy:
<bb 2> [local count: 119292720]:
insert_axis_len.0_1 = insert_axis_len;
ret ={v} {CLOBBER};
ret.rho[0] = insert_axis_len.0_1;
__builtin_memcpy (_3(D), &ret, 32);
ret ={v} {CLOBBER};
return _3(D);
and the partial uninitialized read from it is not what the uninit pass can
diagnose (it's memory walking stops at the first may-def, it does not
prune must-def ranges). But even with -fno-tree-loop-distribute-patterns
-fno-tree-vectorize where we get similar IL as with GCC 11 we do not warn so I
wonder
what fixed it on trunk (when you add those options).
