https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117634
Bug ID: 117634
Summary: memset/struct copy transformation into memset/memset
is not done if not address
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Take:
```
struct S { char a[1024]; };
void f(void*);
void
f3 (struct S *b)
{
struct S a;
__builtin_memset (b, 0, sizeof (*b));
a = *b;
f(&a);
f(b);
}
void
f4 (struct S *b)
{
struct S a;
__builtin_memset (b, 0, sizeof (*b));
a = (struct S){};
f(&a);
}
void
f5 ()
{
struct S a, b;
__builtin_memset (&b, 0, sizeof (b));
a = b;
f(&a);
f(&b);
}
```
These all should be optimized to 2 memset. currently f5 (and f4 which is
already 2 memset) can be optimized to a memset via the code in
optimize_memcpy_to_memset but f3 is not handled.
