Skip to content

Rewrite O(N) recursive templates with O(1) pack expansion #3596

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

Jump to bottom
Open
tenpercent wants to merge 3 commits into
base: mpodkory/generate-tuple-optimizations
Choose a base branch
from
Open

Rewrite O(N) recursive templates with O(1) pack expansion #3596

tenpercent wants to merge 3 commits into from

Conversation

@tenpercent
Copy link
Contributor

@tenpercent tenpercent commented Jan 16, 2026 •
edited
Loading

Summary

  • Rewrite sequence_map_inverse using O(1) depth pack expansion
  • Replace O(N) recursive calculate_element_space_size with fold expression
  • Replace sequence_merge O(log N) recursion with O(1) fold expression

Results

Pattern Before After Reduction
sequence_map_inverse 45 inst, 187ms 10 inst, 10ms 95%
calculate_element_space_size 24 inst, 35ms 10 inst, 9ms 73%
sequence_merge O(log N) depth O(1) depth -

Test Plan

  • Waiting for full CI

PR Stack

# PR Description
1 #3585 sequence_gen with __make_integer_seq
2 #3588 generate_identity_sequences helper
3 #3589 Named functors in transform_tensor_descriptor
4 #3590 container_concat optimization
5 #3596 O(1) pack expansion rewrites
6 #3600 TensorDescriptor/TensorAdaptor lambda elimination

This was referenced Jan 16, 2026
Open
Draft
Open
Open
Open
@tenpercent tenpercent force-pushed the mpodkory/generate-tuple-optimizations branch from 59f0c32 to 5190578 Compare January 16, 2026 17:34
@tenpercent tenpercent force-pushed the mpodkory/recursive-to-pack-expansion branch from 6d792da to f5ada17 Compare January 16, 2026 20:16
@tenpercent tenpercent force-pushed the mpodkory/generate-tuple-optimizations branch from 5190578 to 887bdf2 Compare January 16, 2026 20:16
@tenpercent tenpercent mentioned this pull request Jan 16, 2026
Open
1 task
@tenpercent tenpercent marked this pull request as ready for review January 17, 2026 03:41
@tenpercent
Rewrite sequence_map_inverse using O(1) depth pack expansion
a8c9be9 
Replace O(N) recursive template sequence_map_inverse_impl with
constexpr function and pack expansion for O(1) template depth.

Results:
- sequence_map_inverse: 45 instances, 187ms → 7 instances, 10ms (95% reduction)
@tenpercent
Replace O(N) recursive element space size with O(1) fold expression
e74b611 
Use pack expansion with fold expression to compute element space size
instead of recursive template or recursive lambda.

Results:
- calculate_element_space_size: 24 instances, 35ms → 10 instances, 9ms
- Max template depth: 24 → 23
@tenpercent
Replace sequence_merge O(log N) recursion with O(1) fold expression
9942fd6 
Use operator| with fold expression (Seqs{} | ...) to merge sequences
in O(1) template depth instead of O(log N) binary tree recursion.

- Reduces sequence_merge instantiations from 449 to 167 (63% reduction)
- Total template instantiations: 47,186 → 46,974 (-212)
- ADL finds operator| since Sequence is in ck namespace
@tenpercent tenpercent force-pushed the mpodkory/generate-tuple-optimizations branch from 887bdf2 to 02e42dc Compare January 17, 2026 03:51
@tenpercent tenpercent force-pushed the mpodkory/recursive-to-pack-expansion branch from f5ada17 to 9942fd6 Compare January 17, 2026 03:51
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@illsilin illsilin Awaiting requested review from illsilin illsilin is a code owner

@carlushuang carlushuang Awaiting requested review from carlushuang carlushuang is a code owner

@qianfengz qianfengz Awaiting requested review from qianfengz qianfengz is a code owner

@aosewski aosewski Awaiting requested review from aosewski aosewski is a code owner

@poyenc poyenc Awaiting requested review from poyenc poyenc is a code owner

@geyyer geyyer Awaiting requested review from geyyer geyyer is a code owner

@bartekxk bartekxk Awaiting requested review from bartekxk bartekxk is a code owner

@andriy-ca andriy-ca Awaiting requested review from andriy-ca andriy-ca is a code owner

@afagaj afagaj Awaiting requested review from afagaj afagaj is a code owner

@asleepzzz asleepzzz Awaiting requested review from asleepzzz asleepzzz is a code owner

@ThomasNing ThomasNing Awaiting requested review from ThomasNing ThomasNing is a code owner

@coderfeli coderfeli Awaiting requested review from coderfeli coderfeli is a code owner

@cgmillette cgmillette Awaiting requested review from cgmillette cgmillette is a code owner

@shumway shumway Awaiting requested review from shumway shumway is a code owner

@vidyasagar-amd vidyasagar-amd Awaiting requested review from vidyasagar-amd vidyasagar-amd is a code owner

@vpietila-amd vpietila-amd Awaiting requested review from vpietila-amd vpietila-amd is a code owner

@Snektron Snektron Awaiting requested review from Snektron Snektron is a code owner

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

2 participants

@tenpercent