Re: Rewrite of pure/const pass and nothrow stuff

[Rafael Espindola <espindola at google dot com>]

Sorry for taking so long to reply. Just a small comment.

>  2) There is local variant of the pass.  It can be done during early optimization
>  and at the place original RTL pass executed.  Especially in early
>  optimization we are effective.  Main motivation for doing so early is to strip down EH
>  and dead calls to get early inliner more informed; main motivation for late pass is to avoid
>  dwarf2out from unnecesarily outputting unwind info and being stupid.
>  IPA pass is the only able to handle non-trivial recursion cycles.

The current pass has a hidden ordering problem. If we have

void f(void) {g()};

the pass will mark g as nothrow and that will invalidate f's eh
regions since the call will be in a eh region but will not throw. An
IPA pass could update f to fix it. With your patch, don't we still
have the same problem in the early and RTL passes?

Thanks!
-- 
Rafael Avila de Espindola

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