Avoid function call overhead of pg_popcount() in syslogger.c.

Instead of calling the pg_popcount() function for a single byte, we
can look up the value in the pg_number_of_ones array.

Discussion: https://postgr.es/m/20240401221117.GB2362108%40nathanxps13

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 08efe74cc910c63811464df99637788db18276c7..437947dbb9d66d8c29b5e46c4b50596551980123 100644 (file)
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -898,7 +898,7 @@ process_pipe_input(char *logbuffer, int *bytes_in_logbuffer)
        if (p.nuls[0] == '\0' && p.nuls[1] == '\0' &&
            p.len > 0 && p.len <= PIPE_MAX_PAYLOAD &&
            p.pid != 0 &&
-           pg_popcount((char *) &dest_flags, 1) == 1)
+           pg_number_of_ones[dest_flags] == 1)
        {
            List       *buffer_list;
            ListCell   *cell;