search for: _addcarry_u64

...es in configure output. 1. xapian-binding: checking for /usr/bin/rdoc... no checking for rdoc... /usr/bin/rdoc Looks curious but no problem since it's found anyway. 2. xapian-core when built with GCC: checking whether __builtin_add_overflow is declared... yes ... checking whether _addcarry_u64 is declared... no There is actually _addcarry_u64 in GCC too, but it's in x86intrin.h instead of intrin.h. This is no problem either, since it's superimposed by __builtin_add_overflow anyway. Thanks,

...g ./configure RDOC=/path/to/rdoc or similar), but it looks like the way that's currently being done doesn't actually work. I'll fix that. > 2. xapian-core when built with GCC: > > checking whether __builtin_add_overflow is declared... yes > ... > checking whether _addcarry_u64 is declared... no > > There is actually _addcarry_u64 in GCC too, but it's in x86intrin.h > instead of intrin.h. This is no problem either, since it's superimposed > by __builtin_add_overflow anyway. I think __builtin_add_overflow() is going to be as good an option (and possib...

Hi, For some maybe dumb reasons I try to write a portable version of int128. What is very valuable for this implementation is access to MUL instruction on x86 which provides full 64 x 64 -> 128 bit multiplication. An equally useful on ARM would be UMULH instruction. Well, the way you can access this on clang / GCC is to use __int128 type or use inline assembly. MSVC provides an intrinsic for

...llvm-dev at lists.llvm.org> wrote: > Hi Pawel, > > There is the _mulx_u64 intrinsic, but it currently requires the hardware > flag "-mbmi2". > > https://github.com/Quuxplusone/WideIntProofOfConcept/blob/master/wider.h#L89-L99 > > On Clang 3.8.1 and earlier, the _addcarry_u64 and _subborrow_u64 > intrinsics required the hardware flag `-madx`, even though they didn't use > the hardware ADX/ADOX instructions. Modern GCC and Clang permit the use of > these intrinsics (to generate ADC) even in the absence of `-madx`. > > I think it would be a very good id...