[Bug tree-optimization/67153] [5/6 Regression] integer optimizations 53% slower than std::bitset<>

[ncm at cantrip dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67153

--- Comment #12 from ncm at cantrip dot org ---
As regards hot spots, the program has two:

        int score[7] = { 0, };
        for (Letters word : words)
/**/        if (!(word & ~seven))
                for_each_in_seven([&](Letters letter, int place) {
                    if (word & letter)
/**/                    score[place] += (word == seven) ? 3 : 1;
                });

The first is executed 300M times, the second 3.3M times.
Inserting a counter bump before the second eliminates the slowdown:

                    if (word & letter) {
                        ++count;
/**/                    score[place] += (word == seven) ? 3 : 1;
                    }

This fact seems consequential.  The surrounding for_each_in_seven
loop isn't doing popcounts, but is doing "while (v &= -v)".

I have repeated tests using -m[no-]bmi[2], with identical results
(i.e. no effect).