From: Tom Lane <tgl@sss.pgh.pa.us>
To: John Naylor <johncnaylorls@gmail.com>
cc: Zsolt Parragi <zsolt.parragi@percona.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
        root <tenistarkim@gmail.com>,
        Nathan Bossart <nathandbossart@gmail.com>
Subject: Re: centralize CPU feature detection
In-reply-to: <CANWCAZbKQ2im1r4ztcyfqNh_6gaJzyewabExYrkACNvMNyqxog@mail.gmail.com>
References: <CANWCAZbgEUFw7LuYSVeJ=Tj98R5HoOB1Ffeqk3aLvbw5rU5NTw@mail.gmail.com> <CAN4CZFNpt2tsysM5j8GvhOLqU2fKiPEGW7xGJ987_Avwk7-7ag@mail.gmail.com> <CANWCAZbzmbCmKiCCWNGuC4FLymYfraJ+f1ZiWK3iOUnv9V9_Lg@mail.gmail.com> <CANWCAZYbTHwbt6PxPP_s0tWUZ_UMz_CcN2HMy0sWT+8TX7zSCA@mail.gmail.com> <CAN4CZFMrj1EB9fDQ4+8o-KzVRhh-FM5U3fXPSnc4YmU-LqNuPA@mail.gmail.com> <CANWCAZZez5TX2fQH8Q_K312TC97O-dMQWJPUtLLGQRNBbcYuSQ@mail.gmail.com> <CAN4CZFNWZwk3vv3_cD=Z9DonWsSuwX18mRhc10Ktu3vt3gtaYg@mail.gmail.com> <CANWCAZbKQ2im1r4ztcyfqNh_6gaJzyewabExYrkACNvMNyqxog@mail.gmail.com>
Comments: In-reply-to John Naylor <johncnaylorls@gmail.com>
	message dated "Mon, 23 Feb 2026 22:32:50 +0700"
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Date: Tue, 24 Feb 2026 14:59:47 -0500
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John Naylor <johncnaylorls@gmail.com> writes:
> I've committed 0001.

BF animal rhinoceros isn't happy.  I can reproduce that locally by
doing

$ ./configure ... USE_SLICING_BY_8_CRC32C=3D1
$ make
...
pg_cpu_x86.c: In function 'pg_comp_crc32c_choose':
pg_cpu_x86.c:85:3: error: 'pg_comp_crc32c' undeclared (first use in this f=
unction); did you mean 'pg_comp_crc32c_sb8'?
   pg_comp_crc32c =3D pg_comp_crc32c_sse42;
   ^~~~~~~~~~~~~~
   pg_comp_crc32c_sb8
pg_cpu_x86.c:85:3: note: each undeclared identifier is reported only once =
for each function it appears in
pg_cpu_x86.c:85:20: error: 'pg_comp_crc32c_sse42' undeclared (first use in=
 this function); did you mean 'pg_comp_crc32c_sb8'?
   pg_comp_crc32c =3D pg_comp_crc32c_sse42;
                    ^~~~~~~~~~~~~~~~~~~~
                    pg_comp_crc32c_sb8
pg_cpu_x86.c:108:9: warning: implicit declaration of function 'pg_comp_crc=
32c'; did you mean 'pg_comp_crc32c_sb8'? [-Wimplicit-function-declaration]
  return pg_comp_crc32c(crc, data, len);
         ^~~~~~~~~~~~~~
         pg_comp_crc32c_sb8


It appears that if you want to build pg_cpu_x86.o unconditionally,
you need to make it more proof against the cases it wasn't getting
built in before.

			regards, tom lane