https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110035
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Ever confirmed|0 |1
Severity|normal |enhancement
Last reconfirmed| |2023-05-30
Status|UNCONFIRMED |NEW
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
In the case of x86_64, it is just moving the loads across the operator new, I
think:
vect_SR.14_5 = MEM <vector(2) long unsigned int> [(struct MyClass
&)obj_2(D)];
vect_SR.15_28 = MEM <vector(2) long unsigned int> [(struct MyClass &)obj_2(D)
+ 16];
vect_SR.16_30 = MEM <vector(2) long unsigned int> [(struct MyClass &)obj_2(D)
+ 32];
_6 = operator new (48);
MEM <vector(2) long unsigned int> [(struct MyClass2 *)_6] = vect_SR.14_5;
MEM <vector(2) long unsigned int> [(struct MyClass2 *)_6 + 16B] =
vect_SR.15_28;
MEM <vector(2) long unsigned int> [(struct MyClass2 *)_6 + 32B] =
vect_SR.16_30;
HandleMyClass2 (_6); [tail call]
Other targets is moving across the operator new too:
D.14580.__obj = *obj_2(D);
_6 = operator new (48);
MEM[(struct MyClass2 *)_6].f = D.14580;
More obvious Reduced testcase:
```
struct MyClass
{
unsigned long long arr[128];
};
[[gnu::noipa]]
void sink(void *m){}
void gg(MyClass &a)
{
MyClass c = a;
MyClass *b = new MyClass;
*b = c;
sink(b);
}
```
There might be a dup of this issue too.
