https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59811
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
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CC| |law at redhat dot com
--- Comment #12 from Jeffrey A. Law <law at redhat dot com> ---
So Jan fixed the combine issue when he committed his changes to remove
statements which set write-only variables. That essentially brought the
combiner down to nothing. Hard to believe since it was just a dozen or so
nodes that were determined to be write-only. But that was double-checked by
just hacking out the call to set_writeonly_bit in one of the older compilers I
was testing.
Richi's change to improve DOM's handling of aliased loads helps considerably if
someone were to disable the IPA propagation bits.
Unfortunately we're still burning a lot of time in the alias walking. So we
can't reasonably consider this resolved for gcc-6:
alias stmt walking : 38.67 (64%) usr 0.01 ( 7%) sys 38.64 (64%) wall
2 kB ( 0%) ggc
tree copy propagation : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall
0 kB ( 0%) ggc
combiner : 0.35 ( 1%) usr 0.01 ( 7%) sys 0.36 ( 1%) wall
2709 kB ( 2%) ggc
integrated RA : 2.27 ( 4%) usr 0.00 ( 0%) sys 2.31 ( 4%) wall
6634 kB ( 4%) ggc
LRA hard reg assignment : 4.39 ( 7%) usr 0.01 ( 7%) sys 4.41 ( 7%) wall
0 kB ( 0%) ggc
The alias statement walking is a bit surprising. This is Fortran code after
all, I wouldn't expect a lot of aliasing, I guess it's just a lot of calls into
the alias statement walking code (but I haven't looked to confirm that theory).
I think the RA/LRA times are probably worth some investigation as well once we
get a handle on what's causing alias stmt walking to go nuts.
