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* [Bug tree-optimization/73457] Missed optimizations: count_if on std::array of constants.
[not found] <bug-73457-4@http.gcc.gnu.org/bugzilla/>
@ 2021-08-18 21:57 ` pinskia at gcc dot gnu.org
2021-08-18 22:25 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-18 21:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=73457
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
testcase:
#include <array>
#include <algorithm>
enum event {
stuff,
crap
};
template<typename Cont>
auto count_event(event e, Cont const& events) {
return std::count(events.begin(), events.end(), e);
}
int main() {
std::array<event, 4> events = { stuff, crap, stuff, stuff };
return count_event(stuff, events);
}
^ permalink raw reply [flat|nested] 2+ messages in thread* [Bug tree-optimization/73457] Missed optimizations: count_if on std::array of constants.
[not found] <bug-73457-4@http.gcc.gnu.org/bugzilla/>
2021-08-18 21:57 ` [Bug tree-optimization/73457] Missed optimizations: count_if on std::array of constants pinskia at gcc dot gnu.org
@ 2021-08-18 22:25 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-18 22:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=73457
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
GCC 8+ can handle this at -O3 and above because we can vectorize the loop
(which GCC 7 could not do, I have not looked into why) so DOM is able to
optimize it after unrolling.
GCC 10+ can handle this at -O3 -fno-tree-loop-vectorize (with SLP still
happening) because of r10-1420.
I do think we should be able to optimize this for -O2 though.
^ permalink raw reply [flat|nested] 2+ messages in thread
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[not found] <bug-73457-4@http.gcc.gnu.org/bugzilla/>
2021-08-18 21:57 ` [Bug tree-optimization/73457] Missed optimizations: count_if on std::array of constants pinskia at gcc dot gnu.org
2021-08-18 22:25 ` pinskia at gcc dot gnu.org
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