On Fri, Sep 25, 2020 at 3:32 PM Martin Liška <mli...@suse.cz> wrote:
>
> On 9/25/20 3:18 PM, Richard Biener wrote:
> > On Fri, Sep 25, 2020 at 11:13 AM Martin Liška <mli...@suse.cz> wrote:
> >>
> >> Hello.
> >>
> >> All right, I come up with a rapid speed up that can allow us to remove
> >> the introduced parameter. It contains 2 parts:
> >> - BIT TEST: we allow at maximum a range that is smaller GET_MODE_BITSIZE
> >> - JT: we spent quite some time in density calculation, we can guess it
> >> first
> >> and it leads to a fast bail out.
> >>
> >> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
> >>
> >> Ready to be installed?
> >
> > Err
> >
> > + auto_vec<int> dest_bbs;
> > - auto_bitmap dest_bbs;
> >
> > - bitmap_set_bit (dest_bbs, sc->m_case_bb->index);
> > + if (!dest_bbs.contains (sc->m_case_bb->index))
> > + {
> > + dest_bbs.safe_push (sc->m_case_bb->index);
> > + if (dest_bbs.length () > m_max_case_bit_tests)
> > + return false;
> > + }
>
> That's intentional as m_max_case_bit_tests is a very small number (3) and
> I want to track *distinct* indices in dest_bbs. So dest_bbs.contains
> is a constant operation.
You're storing bb->index and formerly set bb->index bit, what's the difference?
For max 3 elements a vector is OK, of course but there should be a comment
that says this ;) The static const is 'int' so it can in principle
hold up to two billion ;)
> >
> > vec::contains is linear search so no. Was this for the length check?
> > Just do
> >
> > if (bitmap_set_bit (...))
> > {
> > length++;
> > if (length > ...)
>
> I would need here bitmap_count_bits. Do you prefer it?
bitmap_set_bit returns false if the bit was already set so you can
count as you add bits, see the length++ above.
For three elements the vec will be faster though. May I suggest
to use
auto_vec<int, m_max_case_bit_tests> dest_bbs;
then and quick_push rather than safe_push (need to guard the
push with the max_case_bit_test).
Richard.
> Martin
>
> >
> >> Thanks,
> >> Martin
>
