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Date: Tue, 09 Dec 2008 15:43:00 -0000
Subject: [Bug middle-end/38454]  New: [4.4 Regression] memcpy folding breaks -D_FORTIFY_SOURCE=2 protection
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From: "jakub at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
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/* { dg-do compile } */
/* { dg-options "-O2" } */

typedef __SIZE_TYPE__ size_t;

extern inline __attribute__((gnu_inline, always_inline, artificial)) void *
memcpy (void *__restrict dest, const void *__restrict src, size_t len)
{
  return __builtin___memcpy_chk (dest, /* { dg-warning "will always overflow
destination buffer" } */
 src, len, __builtin_object_size (dest, 0));
}

struct S { char buf[10]; } s;

void
foo (void)
{
  char buf[12];
  char *p = buf + 4;
  struct S *q = (struct S *) p;
  memcpy (q, &s, sizeof (s));
}

/* { dg-final { scan-assembler "__memcpy_chk" } } */

FAILs since I've added new memcpy folding.  The memcpy is folded before it is
inlined and so it isn't warned on, nor checked at runtime.  Testing a patch
that will help this as well as e.g. the memset swapped arguments warning.


-- 
           Summary: [4.4 Regression] memcpy folding breaks -
                    D_FORTIFY_SOURCE=2 protection
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: jakub at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38454