[stdlib] Simplify Int.__floordiv__ and friends
#3497
+12
−29
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
soraros
force-pushed
the
fix-int-floordiv
branch
from
ce14b14
to
8ac9226
Compare
soraros
commented
Sep 18, 2024
stdlib/src/builtin/int.mojo
Outdated
| var mod = self - div * rhs | ||
| var divMod = select(((rhs < 0) ^ (self < 0)) & mod, div - 1, div) | ||
| div = select(self > 0 & rhs > 0, div, divMod) |
There was a problem hiding this comment.
The first branch was never taken anyways, since
self > 0 & rhs > 0
=
self > (0 & rhs) > 0
=
self > 0 > 0
=
False
soraros
changed the title
Int.__floordiv__ and friendsInt.__floordiv__ and friends
|
!sync |
modularbot
added
the
imported-internally
JoeLoser
reviewed
Sep 19, 2024
| if ((rhs < 0) ^ (self < 0)) & mod: | ||
| return div - 1, mod + rhs | ||
| return div, mod | ||
| return self // rhs, self % rhs |
There was a problem hiding this comment.
Question By recomputing things, won't this regress performance a bit?
There was a problem hiding this comment.
Both // and % are marked as always_inline and they share most of the code; I just assume that the compiler can see through the defs and do CSE well. I can inline and do a manual dedup if you so prefer.
There was a problem hiding this comment.
As a ref point, UInt also does this.
There was a problem hiding this comment.
I checked and they generates identical assembly.
soraros
force-pushed
the
fix-int-floordiv
branch
2 times, most recently
from
10a8a71
to
933cc33
Compare
soraros
force-pushed
the
fix-int-floordiv
branch
3 times, most recently
from
278467d
to
d64f143
Compare
This comment was marked as outdated.
This comment was marked as outdated.
soraros
force-pushed
the
fix-int-floordiv
branch
from
d64f143
to
c7b4819
Compare
soraros
force-pushed
the
fix-int-floordiv
branch
from
c7b4819
to
2fda091
Compare
soraros
force-pushed
the
fix-int-floordiv
branch
2 times, most recently
from
2dbaaea
to
8ad2a38
Compare
Signed-off-by: Yiwu Chen <210at85@gmail.com>
soraros
force-pushed
the
fix-int-floordiv
branch
from
8ad2a38
to
86f9501
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.