[Bug optimization/14593] New: [tree-ssa] bcopy is mysteriously replaced with memcpy

[Bug optimization/14593] New: [tree-ssa] bcopy is mysteriously replaced with memcpy

[kazu at cs dot umass dot edu]

Reduced from gcc.c-torture/execute/builtins/string-asm-2*

typedef __SIZE_TYPE__ size_t;
extern void abort (void);
extern void bcopy (const void *, void *, size_t);

char y[64] = "foX";

void *
memcpy (void *d, const void *s, size_t n)
{
  char *dst = (char *) d;
  const char *src = (const char *) s;
  while (n--)
    *dst++ = *src++;
  return (char *) d;
}

int
main (void)
{
  bcopy (y + 1, y + 2, 3);
  if (y[3] != 'X')
    abort ();

  return 0;
}

With -O0, bcopy stays as is in the final assembly output.
With -O1 and above, bcopy is somehow transformed into memcpy.

This problem seems to occur at expand-time.

On mainline, this problem does not exist.

-- 
           Summary: [tree-ssa] bcopy is mysteriously replaced with memcpy
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: h8300-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14593

[Bug optimization/14593] [tree-ssa] bcopy is mysteriously replaced with memcpy

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-03-16 04:34 -------
Note that on this testcase, bcopy must stay as is because
source and destination of bcopy overlap.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14593

[Bug optimization/14593] [tree-ssa] bcopy is mysteriously replaced with memcpy

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-16 04:43 -------
This is an almost exact (very close in fact references the same test case even) dup of bug 14197.

*** This bug has been marked as a duplicate of 14197 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14593