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[Bug default/24965] [dwz] Faster hashing using native insns



https://sourceware.org/bugzilla/show_bug.cgi?id=24965

Martin Liška <marxin.liska at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |marxin.liska at gmail dot com

--- Comment #2 from Martin Liška <marxin.liska at gmail dot com> ---
I do welcome the attempt to adapt the crc32 instructions. If I see correctly,
the instructions are available on x86_64 since SSE 4.2. Which should be
available for the vast majority of CPUs.

Note that one can use directly i386 builtins like:
static inline uint64_t _mm_crc32_u64(uint64_t crc, uint64_t value) {
  return __builtin_ia32_crc32qi (crc, value);
}

plus you'll need to use -msse42, or -mcrc32. So I would recommend to use a
start detection of the ISA and then use the instruction.

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