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). 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. Thanks, Richard
