url.c:1564:69: warning: shifting a negative signed value is undefined [-Wshift-negative-value]
                        pstate->cur_lineno = line_number ? line_number - 1 : (int64) - 1 << 63;
                                                                             ~~~~~~~~~~~ ^
heap.c:1615:19: warning: equality comparison with extraneous parentheses [-Wparentheses-equality]
                if ((relstorage == RELSTORAGE_PARQUET))
                     ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~

planner.c:679:26: warning: equality comparison with extraneous parentheses [-Wparentheses-equality]
                        if ((resourceLife == QRL_ONCE)) {
                             ~~~~~~~~~~~~~^~~~~~~~~~~

./regc_locale.c:358:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isdigit((unsigned char) c));
                ~ ^  ~
./regc_locale.c:364:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isalpha((unsigned char) c));
                ~ ^  ~
./regc_locale.c:370:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isalnum((unsigned char) c));
                ~ ^  ~
./regc_locale.c:376:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isupper((unsigned char) c));
                ~ ^  ~
./regc_locale.c:382:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && islower((unsigned char) c));
                ~ ^  ~
./regc_locale.c:388:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isgraph((unsigned char) c));
                ~ ^  ~
./regc_locale.c:394:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isprint((unsigned char) c));
                ~ ^  ~
./regc_locale.c:400:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && ispunct((unsigned char) c));
                ~ ^  ~
./regc_locale.c:406:12: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        return (c >= 0 && c <= UCHAR_MAX && isspace((unsigned char) c));
                ~ ^  ~
./regc_locale.c:412:8: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        if (c >= 0 && c <= UCHAR_MAX)
            ~ ^  ~
./regc_locale.c:420:8: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
        if (c >= 0 && c <= UCHAR_MAX)
            ~ ^  ~
11 warnings generated.

fe-exec.c:2389:13: warning: comparison of unsigned enum expression < 0 is always false [-Wtautological-compare]
        if (status < 0 || status >= sizeof pgresStatus / sizeof pgresStatus[0])
            ~~~~~~ ^ ~

/Users/wuhong/Desktop/2016-Pivotal/Code/github/incubator-hawq/src/bin/gpfdist/src/gpfdist/gpfdist.c:2515:41: warning: comparison of unsigned expression >= 0 is always true
      [-Wtautological-compare]
                if (r->in.davailable - buf_space_left >= 0)
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~

pg_filesystem.c:387:11: warning: comparison of unsigned enum expression < 0 is always false [-Wtautological-compare]
        if(ftype < 0 || ftype >= FSYS_FUNC_TOTALNUM)
           ~~~~~ ^ ~
pg_filesystem.c:397:11: warning: comparison of unsigned enum expression < 0 is always false [-Wtautological-compare]
        if(ftype < 0 || ftype >= FSYS_FUNC_TOTALNUM)
           ~~~~~ ^ ~
2 warnings generated.