Jakub Jelinek <ja...@redhat.com> wrote: > On Fri, Nov 20, 2020 at 11:08:41AM +0100, Stefan Kanthak wrote: >> The construction of the "magic" constants 0x55...55, 0x33...33, 0x0f...0f >> and 0x01...01 in __popcountSI2 and __popcountDI2 with macros is awkward; >> these constants can simply be written as ((UWtype) ~0 / 3), >> ((UWtype) ~0 / 5), ((UWtype) ~0 / 17) and ((UWtype) ~0 / 255) > > (UWtype) ~0 will only work if UWtype is unsigned int,
Hmmm... U*type is but unsigned, and both (__uint128_t) ~0 / 3 as well as (unsigned long long) ~0 / 3 yield the expected constant 0x55...55 here, and the other constants of course too. > don't you really mean ~(UWtype) 0 instead? This is indeed the better^Wcorrect solution. Corrected patch attached. Stefan
libgcc2.patch
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