https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105145
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2022-04-05
Status|UNCONFIRMED |NEW
CC| |rsandifo at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
There is no infrastructure to retain debug information for memory contents
(which includes address-taken local variables which can eventually become
registers later). IIRC Richard Sandiford developed some prototype patches to
try improve this a bit a few years ago.
In particular here we have before DSE1
[t.c:11:8] l_158(address-taken) = [t.c:11:16] &l_141(address-taken);
...
l_158(address-taken) ={v} {CLOBBER(eol)};
and l_158 is otherwise unused so DSE elides the store. If we'd call
update_address_taken before DSE we'd rewrite l_158 into SSA form and
then DSE/DCE would retain a # DEBUG stmt for the value. In this case
it is FRE1 which elides all uses of the variable.
