[Bug c/55999] New: gcc 4.7.2 -O2 -floop-parallelize-all generates incorrect code

[nfxjfg at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55999



             Bug #: 55999

           Summary: gcc 4.7.2 -O2  -floop-parallelize-all generates

                    incorrect code

    Classification: Unclassified

           Product: gcc

           Version: 4.7.2

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: nfx...@gmail.com





struct s {

    int8_t num, c;

    int8_t xs[4], ys[4];

};



void stuff(struct s *desc)

{

    int n;

    for (n = 0; n < desc->num; n++) {

        desc->xs[n] = (n == 1 || n == 2) ? desc->c : 0;

        desc->ys[n] = (n == 1 || n == 2) ? desc->c : 0;

    }

}



desc->xs[0] is not 0 after calling this function, although it should be.



The attached log was generated with gcc -v -save-temps  gcc_issue.c

gcc_issue_main.c -Wall -Wextra -O2  -floop-parallelize-all  > log.txt 2>&1



The assert in gcc_issue_main.c should not be triggered (and is not triggered

when removing -O2 or -floop-parallelize-all).