https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107250
Bug ID: 107250
Summary: Load unnecessarily happens before malloc
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jmuizelaar at mozilla dot com
Target Milestone: ---
The following code will be compiled with the load of next happening before the
call to malloc. This generates worse code than if the load is delayed until
after the call to malloc.
struct Foo {
Foo* next;
};
void ctx_push(Foo* f) {
Foo tmp = { f->next };
Foo *n = (Foo*)malloc(sizeof(Foo));
*n = tmp;
f->next = n;
}
Manually moving the load in this example improves the generated code:
struct Foo {
Foo* next;
};
void ctx_push(Foo* f) {
Foo *n = (Foo*)malloc(sizeof(Foo));
Foo tmp = { f->next };
*n = tmp;
f->next = n;
}
https://gcc.godbolt.org/z/TnMj1c636
