https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110035
user202729 <user202729 at protonmail dot com> changed:
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CC| |user202729 at protonmail dot
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--- Comment #17 from user202729 <user202729 at protonmail dot com> ---
Created attachment 58280
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58280&action=edit
Possible patch to address the issue in case the intervening function is pure
instead of `operator new`.
I wrote a patch (attached) that allows the optimization to be performed if the
intervening function is pure instead of `operator new`.
With this patch, each of the functions in the following code will use only one
memory store instead of two.
```
#include <array>
#include <cstdint>
struct MyClass
{
std::array<uint64_t, 2> arr;
};
// Prevent optimization
void sink(void *m) {
asm volatile("" : : "g"(m) : "memory");
}
__attribute__((pure)) int f();
int g1(MyClass a)
{
MyClass b;
MyClass c = a;
int result=f();
b = c;
sink(&b);
return result;
}
int g2(MyClass a)
{
MyClass b;
MyClass c = a;
int result=f();
b = c;
sink(&b);
return result;
}
int g3(MyClass&& a)
{
MyClass b;
MyClass c = a;
int result=f();
b = c;
sink(&b);
return result;
}
```
It would be helpful if someone can review the patch.
