On 2019-Feb-14, Tom Lane wrote:
> Then the correct test to see if we want to build pg_popcount.c (BTW,
> please pick a less generic name for that) and the choose function
> is whether we have *both* HAVE__BUILTIN_POPCOUNT and nonempty
> CFLAGS_POPCNT.
I used pg_bitutils_sse42.c to host the specially-compiled functions.
The name is not entirely correct, but seems clear enough.
I noticed in Compiler Explorer that some (ancient?) Power cpus
implement instruction "popcntb", and GCC support for those uses
-mpopcntb switch enabling __builtin_popcount() to use it. I added the
switch to configure.in but I'm not sure how well that will work ... I
don't know if this is represented in buildfarm.
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Álvaro Herrera https://www.2ndQuadrant.com/
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