Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[mypyc] Avoid boxing/unboxing when coercing between tuple types #14899

Merged
merged 2 commits into from
Mar 20, 2023

Conversation

JukkaL
Copy link
Collaborator

@JukkaL JukkaL commented Mar 14, 2023

Instead, coerce each tuple item individually. This makes some coercions between tuple types much faster, primarily because there is less (or no) allocation and deallocation going on.

This speeds up the raytrace benchmark by about 7% (when using native floats).

Related to mypyc/mypyc#99.

JukkaL added 2 commits March 14, 2023 19:33
Instead, coerce each tuple item individually. This makes some
coercions between tuple types much faster, primarily because there is
less (or no) allocation and deallocation going on.

This speeds up the raytrace benchmark by about 7% (when using native
floats).

Related to mypyc/mypyc#99.
@@ -666,13 +665,11 @@ L0:
return r0
def g():
r0 :: tuple[int, int]
r1 :: object
r2 :: tuple[int64, int64]
r1 :: tuple[int64, int64]
L0:
r0 = (2, 4)
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It's a little unfortunate that this remains in the IR, but it's nothing DCE can't fix if we ever implement it.

tuple_T288 CPyDef_g(void) {
    tuple_T2II cpy_r_r0;
    tuple_T288 cpy_r_r1;
CPyL0: ;
    cpy_r_r0.f0 = 2;
    cpy_r_r0.f1 = 4;
    CPyTagged_INCREF(cpy_r_r0.f0);
    CPyTagged_INCREF(cpy_r_r0.f1);
    CPyTagged_DECREF(cpy_r_r0.f0);
    CPyTagged_DECREF(cpy_r_r0.f1);
    cpy_r_r1.f0 = 1;
    cpy_r_r1.f1 = 2;
    return cpy_r_r1;
}

Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The C compiler may optimize some of these away. Also, optimizing these shouldn't be too difficult in mypyc. Added mypyc/mypyc#983 to track this.

Comment on lines +369 to +370
# We can't reuse register values, since they can be modified.
if not isinstance(item, Register):
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is not a blocking comment, moreso for my own learning. What situations exist where a register is modified during the coerce operation?

Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is about code like this:

    t = (n, 0)
    n += 1
    t2: tuple[float, float] = t

We can't use n to refer to the first item of t when constructing t2, since n was incremented on line 2.

Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ah right. I should've thought of that, painfully obvious now you show it. Thanks!

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

2 participants