When can 'Ofast' optimization bring negative optimization

Revision en3, by AcceptedIsRealAbility, 2019-08-01 15:10:59

We all know that this line in C++#pragma GCC optimize("Ofast") can optimize most programs.

But specially, the accident(maybe?) happens on me.

Today, I was solving the problem 455D - Серега и веселье with fhq-treap, And I submitted two submissions: 58122597 and 58123225, when first one got AC with no optimization, and the second with 'Ofast' optimization got TLE on test 25.

So I just want to know what kind of programs the 'Ofast' optimization can bring negative optimization?

Tags ofast optimization

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en3 English AcceptedIsRealAbility 2019-08-01 15:10:59 1 Tiny change: 'he problem[problem:4' -> 'he problem [problem:4'
en2 English AcceptedIsRealAbility 2019-08-01 15:10:30 18
en1 English AcceptedIsRealAbility 2019-08-01 15:09:45 579 Initial revision (published)