https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101501
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2021-07-22
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
Status|UNCONFIRMED |ASSIGNED
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
niter analysis computes
Analyzing # of iterations of loop 2
exit condition [a_lsm.5_10 * 52, + , 204] != 0
bounds on difference of bases: -255 ... 0
result:
# of iterations (a_lsm.5_10 * 52) / 52, bounded by 63
but then
Loop 2 iterates at most 14 times.
Loop 2 likely iterates at most 14 times.
because we have nb_iterations_upper_bound set on the loop. That upper bound
is set by the vectorizer which vectorizes the loop but then it's immediately
removed again because the runtime profitability check optimizes to 1 != 0?!
With -fno-vect-cost-model things don't fare any better but -fno-tree-vectorize
fixes the issue.
