Add missing guard for __builtin_constant_p

Oversight in commit e2809e3a1. While at it, use pg_integer_constant_p
in master.

Discussion: https://postgr.es/m/CANWCAZbOha-x5MCreQn3TRA56VdKWNMAKMy3fAV1kJSw9Vp4pw@mail.gmail.com
Backpatch-through: 18

diff --git a/src/include/port/pg_crc32c.h b/src/include/port/pg_crc32c.h
index ae008118ea818a6f406fd746da19ab9430d589a8..833d4b7df9673360925a6f8e676527cb3bdaa3fb 100644 (file)
--- a/src/include/port/pg_crc32c.h
+++ b/src/include/port/pg_crc32c.h
@@ -70,6 +70,7 @@ static inline
 pg_crc32c
 pg_comp_crc32c_dispatch(pg_crc32c crc, const void *data, size_t len)
 {
+#ifdef HAVE__BUILTIN_CONSTANT_P
        if (__builtin_constant_p(len) && len < 32)
        {
                const unsigned char *p = (const unsigned char *) data;
@@ -91,6 +92,9 @@ pg_comp_crc32c_dispatch(pg_crc32c crc, const void *data, size_t len)
        else
                /* Otherwise, use a runtime check for AVX-512 instructions. */
                return pg_comp_crc32c(crc, data, len);
+#else
+       return pg_comp_crc32c(crc, data, len);
+#endif                                                 /* HAVE__BUILTIN_CONSTANT_P */
 }
 
 #elif defined(USE_SSE42_CRC32C_WITH_RUNTIME_CHECK)