extern void abort (void);
extern void *memset (void *s, int c, __SIZE_TYPE__ n);
struct S { int i[16]; };
struct S *p;
void __attribute__((noinline))
foo(struct S *a, struct S *b) { a->i[0] = -1; p = b; }
void test (void)
{
struct S a, b;
memset (&a.i[0], '\0', sizeof (a.i));
memset (&b.i[0], '\0', sizeof (b.i));
foo (&a, &b);
*p = a;
*p = b;
if (b.i[0] != -1)
abort ();
}
int main()
{
test();
return 0;
}
tree DSE removes the *p = a store wrongly. Non-executable testcase:
struct S { int i[16]; };
struct S *p;
void foo(struct S *, struct S *);
void test (void)
{
struct S a, b;
foo (&a, &b);
*p = a;
*p = b;
}
--
Summary: [4.3/4.4 Regression] tree DSE is broken
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rguenth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35472
