Skip to content

bpo-46372: Try to mutate the LHS during fast float ops #30594

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.

Sign up for GitHub

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

Closed
brandtbucher wants to merge 18 commits into from
Closed

bpo-46372: Try to mutate the LHS during fast float ops #30594

Changes from 1 commit
Commits
Show all changes
18 commits
Select commit Hold shift + click to select a range
cf64e13
Perform specialized ops in-place when possible
brandtbucher Jan 11, 2022
5e49a13
Break out common logic
brandtbucher Jan 12, 2022
f7187d9
Clean things up a bit
brandtbucher Jan 12, 2022
dd19cec
Clean up macro
brandtbucher Jan 12, 2022
78cc5c4
Simplify the "small" int case
brandtbucher Jan 13, 2022
218b10b
blurb add
brandtbucher Jan 14, 2022
505fd8e
Catch up with main
brandtbucher Jan 18, 2022
6b4cc6d
Apply first round of code revew comments
brandtbucher Jan 18, 2022
f21a813
Fix 32-bit Windows errrors
brandtbucher Jan 19, 2022
d6a69d5
Perform the inplace checks when specializing
brandtbucher Jan 19, 2022
f11cf6d
Remove duplicate code
brandtbucher Jan 19, 2022
b6f041a
Simplify things further
brandtbucher Jan 19, 2022
eb586b1
Remove int and refcount == 2 optimizations
brandtbucher Jan 19, 2022
def9c64
Catch up with main
brandtbucher Jan 21, 2022
6e262ba
Revert int changes
brandtbucher Jan 24, 2022
37fab55
Catch up with main
brandtbucher Jan 28, 2022
04f186c
Add the "adaptive superinstructions" back
brandtbucher Feb 1, 2022
e0d0042
Catch up with main
brandtbucher Feb 1, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
Catch up with main
  • Loading branch information
@brandtbucher
brandtbucher committed Jan 28, 2022
commit 37fab55bd8f8fcd679d2fa9cc9b481b0ada03e56
5 changes: 3 additions & 2 deletions Python/ceval.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -859,6 +859,7 @@ static const binaryfunc binary_ops[] = {

#define BINARY_OP_FAST_FLOAT(OP) \
do { \
assert(cframe.use_tracing == 0); \
PyObject *lhs = SECOND(); \
PyObject *rhs = TOP(); \
DEOPT_IF(!PyFloat_CheckExact(lhs), BINARY_OP); \
Expand All @@ -871,15 +872,15 @@ static const binaryfunc binary_ops[] = {
STACK_SHRINK(1); \
if (Py_REFCNT(lhs) == 1) { \
Copy link
Copy Markdown
Member

@gvanrossum gvanrossum Jan 31, 2022

Choose a reason for hiding this comment

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

Would there be any benefit in checking whether perhaps rhs has a refcount of 1, in case lhs doesn't? While people are probably more likely to write return x+1 rather than return 1+x (though even I could sometimes see a reason to do that, from "rhyming" with some other operations or just how the textbook presents the formula), writing return 2*x is more likely than return x*2. And of course for asymmetric operations you may not have a choice, like return 1/x.

Of course, there's a cost (more code, more branches). There's also the fact that += and friends steer this in the direction you're taking here.

Copy link
Copy Markdown
Member Author

@brandtbucher brandtbucher Feb 1, 2022

Choose a reason for hiding this comment

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

Of course, there's a cost (more code, more branches). There's also the fact that += and friends steer this in the direction you're taking here.

Yeah, those are my main motivations for sticking with the LHS here.

PyFloat_AS_DOUBLE(lhs) = d; \
Copy link
Copy Markdown
Member

@gvanrossum gvanrossum Jan 31, 2022

Choose a reason for hiding this comment

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

Presumably (see PEP 674) Victor won't like this use of a macro as a target. :-)

Nevertheless, this whole macro is so nice and straightforward compared to ints!

DISPATCH(); \
NOTRACE_DISPATCH(); \
} \
Py_DECREF(lhs); \
Comment thread
brandtbucher marked this conversation as resolved.
Outdated
PyObject *res = PyFloat_FromDouble(d); \
SET_TOP(res); \
if (res == NULL) { \
goto error; \
} \
DISPATCH(); \
NOTRACE_DISPATCH(); \
} while (0)


Expand Down
You are viewing a condensed version of this merge commit. You can view the full changes here.