On Tue, May 30, 2017 at 4:35 PM, Richard Sandiford <richard.sandif...@linaro.org> wrote: > Yuri Gribov <tetra2...@gmail.com> writes: >> On Tue, May 30, 2017 at 11:35 AM, Richard Sandiford >> <richard.sandif...@linaro.org> wrote: >>> Yuri Gribov <tetra2...@gmail.com> writes: >>>> On Tue, May 30, 2017 at 7:35 AM, Richard Sandiford >>>> <richard.sandif...@linaro.org> wrote: >>>>> Yuri Gribov <tetra2...@gmail.com> writes: >>>>>> From 330209f721a598ec393dcb5d62de3457ee282153 Mon Sep 17 00:00:00 2001 >>>>>> From: Yury Gribov <tetra2...@gmail.com> >>>>>> Date: Fri, 26 May 2017 07:53:10 +0100 >>>>>> Subject: [PATCH 3/4] Added bool conversion for wide_ints. >>>>>> >>>>>> gcc/ >>>>>> 2017-05-26 Yury Gribov <tetra2...@gmail.com> >>>>>> >>>>>> * wide-int.cc (wi::zero_p_large): New method. >>>>>> * wide-int.h (wi::zero_p): New method. >>>>> >>>>> Do you still need this bit? It looks like it isn't used by the other >>>>> parts of the series. >>>>> >>>>> The idea was that wi::eq_p (x, 0) (or just x == 0, if x is a >>>>> wide-int-based type) is supposed to be as fast as a dedicated zero check. >>>>> It'd be OK to have a helper function anyway, but it should probably be >>>>> defined using wi::eq_p. >>>>> >>>>> The zero_p_large fallback can never return true, since a zero of >>>>> any precision will have a length of 1. >>>> >>>> Thanks Richard, I'll update the patch. The bool check is used in >>>> successive patch (4/4), in >>>> widest_int mask = wi::to_widest (@2); >>>> bool mask_all_ones_p = !(mask & (mask + 1)); >>> >>> Ah, OK. That's equivalent to mask == -1 (or wi::eq_p (@2, -1), to avoid >>> the temporary). >> >> Hm, is it? Current check ensures that N consecutive LSBs are set, not >> that all bits are set. Perhaps variable name should be changed to >> reflect this better. > > Sorry, yeah, was going off the variable name rather than what the > test actually did... > >>> I think it'd be better to use one of those instead. >>> There's an argument that if ! is defined, it should return an integer >>> of the same precision as the argument. >> >> True. Perhaps I should make separate >> wide_int operator !() >> and >> bool operator bool() > > Why not just a comparison? It seems clearer IMO.
Ok, will do. Guess I won't leave a trace in histor^W wide-int.h this time. -Y
