https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61619
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
CC| |jamborm at gcc dot gnu.org
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
._94/3491 (constexpr const long unsigned int ._94 [1]) @0x7ffff1d5ca90
Type: variable definition analyzed
Visibility: prevailing_def_ironly artificial
References:
Referring: main/3232 (read)
Availability: available
Varpool flags: initialized read-only const-value-known
Ok, for the above SRA fails to do a scalar replacement and value-numbering
doesn't even reach the aggregate copy from the constant initializer.
That's because only PRE exposes it and PRE doesn't do all the fancy VN
tricks.
I suppose I have to look closer at some point. Interesting testcase
showing possible issues with C++ constexpr initializers.
Note that we also have
MEM[(char * {ref-all})&S] = MEM[(char * {ref-all})&._94];
but this aggregate copy has sizeof (long) so we could have optimized it
(it's ref-all already) to use an integer type.
This is lowered from
array<long unsigned int, 1ul>::array (&S, (const struct initializer_list &)
&TARGET_EXPR <D.64552, {._M_array=(const long unsigned int *) &._94,
._M_len=1}>)
to
D.64552._M_array = &._94;
D.64552._M_len = 1;
try
{
array<long unsigned int, 1ul>::array (&S, &D.64552);
}
which eventually ends up calling memmove which we optimize to the aggregate
assignment.
