[Bug tree-optimization/55949] New: __builtin_object_size size passed to memcpy_chk is incorrect

[rmansfield at qnx dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55949



             Bug #: 55949

           Summary: __builtin_object_size size passed to memcpy_chk is

                    incorrect

    Classification: Unclassified

           Product: gcc

           Version: 4.6.4

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: tree-optimization

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

        ReportedBy: rmansfi...@qnx.com





float m[3][3];

 float im[3][3];



 memcpy( im, m, sizeof( im ) );



$ ./xgcc -B. ~/r.i -O2 -S

In function 'memcpy',

    inlined from 'foo' at /home/ryan/r.i:35:8:

/home/ryan/r.i:7:3: warning: call to __builtin___memcpy_chk will always

overflow destination buffer [enabled by default]



generates:



        mov     r2, #36

        mov     r3, #12



        bl      __memcpy_chk





This happens on the 4.6 branch, but not in 4.7/4.8. It stopped happening on

trunk after this change:



http://gcc.gnu.org/viewcvs?view=revision&revision=179620



but then it becomes a direct call to memcpy instead of __memcpy_chk