BE-303: HashQL: Split MIR basic blocks by target support

[indietyp]

🌟 What is the purpose of this PR?

Introduce a MIR execution-analysis pass that splits basic blocks into contiguous regions with uniform target support, returning per-block target affinities for downstream scheduling.

🔍 What does this change?

• Add a basic-block splitting pass that remaps block IDs, inserts Goto chains between split regions, and returns target affinities.
• Add unit and snapshot coverage for splitting behavior and cost remapping.
• Extend execution-analysis data structures to support target bitsets/arrays and cost remapping.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• does not modify any publishable blocks or libraries, or modifications do not need publishing

📜 Does this require a change to the docs?

The changes in this PR:

• are internal and do not require a docs change

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

• do not affect the execution graph

🛡 What tests cover this?

• New unit tests and snapshot coverage for the splitting pass.

❓ How to test this?

• Run the hashql-mir test suite that includes execution spli

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Project	Deployment	Actions	Updated (UTC)
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[cursor]

PR Summary

Medium Risk
Medium risk because it changes MIR control-flow/block layout (ID remapping and inserted Goto chains) and updates cost indexing utilities; incorrect splitting/remapping could break downstream analyses despite strong test coverage.

Overview
Adds a new execution::splitting pass (BasicBlockSplitting) that partitions MIR BasicBlocks whenever per-statement target support changes, remaps all BasicBlockId references, inserts Goto chains between split blocks, and produces per-block TargetBitSet affinities for downstream scheduling.

Refactors execution-target plumbing to support this: reworks TargetId into an enum implementing Id, introduces TargetArray/TargetBitSet (using new core IdArray and a re-implemented FiniteBitSet), and extends StatementCostVec with offset remapping/helpers needed after block splitting.

Adds extensive unit + snapshot tests covering region counting, splitting behavior, block-reference rewriting, and cost remapping, plus small core utilities (IdSlice::windows, feature gates) to support the new structures.

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Your organization requires reapproval when changes are made, so Graphite has dismissed approvals. See the output of git range-diff at https://github.com/hashintel/hash/actions/runs/22188101486

[graphite-app]

Merge activity

• Feb 19, 3:27 PM UTC: Graphite rebased this pull request, because this pull request is set to merge when ready.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[github-actions]

Benchmark results

@rust/hash-graph-benches – Integrations

policy_resolution_large

Function	Value	Mean	Flame graphs
resolve_policies_for_actor	user: empty, selectivity: high, policies: 2002	$$26.6 \mathrm{ms} \pm 178 \mathrm{μs}\left({\color{gray}1.18 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: low, policies: 1	$$3.19 \mathrm{ms} \pm 12.5 \mathrm{μs}\left({\color{gray}-0.029 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: medium, policies: 1001	$$11.7 \mathrm{ms} \pm 93.7 \mathrm{μs}\left({\color{gray}-1.494 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: high, policies: 3314	$$41.8 \mathrm{ms} \pm 344 \mathrm{μs}\left({\color{gray}0.194 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: low, policies: 1	$$13.6 \mathrm{ms} \pm 71.3 \mathrm{μs}\left({\color{gray}0.567 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: medium, policies: 1526	$$23.5 \mathrm{ms} \pm 179 \mathrm{μs}\left({\color{gray}2.80 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: high, policies: 2078	$$27.6 \mathrm{ms} \pm 173 \mathrm{μs}\left({\color{gray}-0.004 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: low, policies: 1	$$3.50 \mathrm{ms} \pm 23.4 \mathrm{μs}\left({\color{gray}1.13 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: medium, policies: 1033	$$12.7 \mathrm{ms} \pm 81.9 \mathrm{μs}\left({\color{gray}-1.334 \mathrm{\%}}\right) $$	Flame Graph

policy_resolution_medium

Function	Value	Mean	Flame graphs
resolve_policies_for_actor	user: empty, selectivity: high, policies: 102	$$3.57 \mathrm{ms} \pm 16.4 \mathrm{μs}\left({\color{gray}-0.530 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: low, policies: 1	$$2.81 \mathrm{ms} \pm 12.6 \mathrm{μs}\left({\color{gray}0.195 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: medium, policies: 51	$$3.15 \mathrm{ms} \pm 18.4 \mathrm{μs}\left({\color{gray}0.610 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: high, policies: 269	$$4.92 \mathrm{ms} \pm 20.4 \mathrm{μs}\left({\color{gray}-0.226 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: low, policies: 1	$$3.36 \mathrm{ms} \pm 13.8 \mathrm{μs}\left({\color{gray}0.209 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: medium, policies: 107	$$3.90 \mathrm{ms} \pm 16.7 \mathrm{μs}\left({\color{gray}-0.146 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: high, policies: 133	$$4.21 \mathrm{ms} \pm 22.1 \mathrm{μs}\left({\color{gray}-0.307 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: low, policies: 1	$$3.23 \mathrm{ms} \pm 15.7 \mathrm{μs}\left({\color{gray}0.089 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: medium, policies: 63	$$3.82 \mathrm{ms} \pm 21.4 \mathrm{μs}\left({\color{gray}0.093 \mathrm{\%}}\right) $$	Flame Graph

policy_resolution_none

Function	Value	Mean	Flame graphs
resolve_policies_for_actor	user: empty, selectivity: high, policies: 2	$$2.54 \mathrm{ms} \pm 8.74 \mathrm{μs}\left({\color{gray}-0.609 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: low, policies: 1	$$2.50 \mathrm{ms} \pm 9.54 \mathrm{μs}\left({\color{gray}0.084 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: medium, policies: 1	$$2.61 \mathrm{ms} \pm 11.2 \mathrm{μs}\left({\color{gray}0.310 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: high, policies: 8	$$2.87 \mathrm{ms} \pm 15.1 \mathrm{μs}\left({\color{gray}0.255 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: low, policies: 1	$$2.66 \mathrm{ms} \pm 10.2 \mathrm{μs}\left({\color{gray}-0.027 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: medium, policies: 3	$$2.95 \mathrm{ms} \pm 13.5 \mathrm{μs}\left({\color{gray}0.681 \mathrm{\%}}\right) $$	Flame Graph

policy_resolution_small

Function	Value	Mean	Flame graphs
resolve_policies_for_actor	user: empty, selectivity: high, policies: 52	$$2.90 \mathrm{ms} \pm 12.5 \mathrm{μs}\left({\color{gray}0.557 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: low, policies: 1	$$2.61 \mathrm{ms} \pm 12.1 \mathrm{μs}\left({\color{gray}0.913 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: empty, selectivity: medium, policies: 25	$$2.77 \mathrm{ms} \pm 13.2 \mathrm{μs}\left({\color{gray}0.254 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: high, policies: 94	$$3.29 \mathrm{ms} \pm 13.1 \mathrm{μs}\left({\color{gray}-0.530 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: low, policies: 1	$$2.88 \mathrm{ms} \pm 14.8 \mathrm{μs}\left({\color{gray}1.38 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: seeded, selectivity: medium, policies: 26	$$3.11 \mathrm{ms} \pm 15.9 \mathrm{μs}\left({\color{gray}0.308 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: high, policies: 66	$$3.23 \mathrm{ms} \pm 14.7 \mathrm{μs}\left({\color{gray}-0.067 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: low, policies: 1	$$2.82 \mathrm{ms} \pm 11.2 \mathrm{μs}\left({\color{gray}0.638 \mathrm{\%}}\right) $$	Flame Graph
resolve_policies_for_actor	user: system, selectivity: medium, policies: 29	$$3.08 \mathrm{ms} \pm 13.9 \mathrm{μs}\left({\color{gray}0.406 \mathrm{\%}}\right) $$	Flame Graph

read_scaling_complete

Function	Value	Mean	Flame graphs
entity_by_id;one_depth	1 entities	$$38.7 \mathrm{ms} \pm 164 \mathrm{μs}\left({\color{gray}-0.128 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;one_depth	10 entities	$$74.9 \mathrm{ms} \pm 349 \mathrm{μs}\left({\color{gray}-1.123 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;one_depth	25 entities	$$42.4 \mathrm{ms} \pm 151 \mathrm{μs}\left({\color{gray}0.395 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;one_depth	5 entities	$$45.3 \mathrm{ms} \pm 175 \mathrm{μs}\left({\color{gray}0.850 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;one_depth	50 entities	$$52.7 \mathrm{ms} \pm 242 \mathrm{μs}\left({\color{gray}0.548 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;two_depth	1 entities	$$40.4 \mathrm{ms} \pm 196 \mathrm{μs}\left({\color{gray}0.296 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;two_depth	10 entities	$$415 \mathrm{ms} \pm 989 \mathrm{μs}\left({\color{gray}1.52 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;two_depth	25 entities	$$88.6 \mathrm{ms} \pm 486 \mathrm{μs}\left({\color{lightgreen}-5.946 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;two_depth	5 entities	$$84.2 \mathrm{ms} \pm 406 \mathrm{μs}\left({\color{gray}0.380 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;two_depth	50 entities	$$305 \mathrm{ms} \pm 1.16 \mathrm{ms}\left({\color{red}10.9 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;zero_depth	1 entities	$$14.8 \mathrm{ms} \pm 69.2 \mathrm{μs}\left({\color{gray}2.04 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;zero_depth	10 entities	$$14.8 \mathrm{ms} \pm 82.1 \mathrm{μs}\left({\color{gray}1.55 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;zero_depth	25 entities	$$15.0 \mathrm{ms} \pm 61.0 \mathrm{μs}\left({\color{gray}0.896 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;zero_depth	5 entities	$$14.7 \mathrm{ms} \pm 76.9 \mathrm{μs}\left({\color{gray}-0.290 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id;zero_depth	50 entities	$$17.5 \mathrm{ms} \pm 112 \mathrm{μs}\left({\color{gray}-1.141 \mathrm{\%}}\right) $$	Flame Graph

read_scaling_linkless

Function	Value	Mean	Flame graphs
entity_by_id	1 entities	$$14.9 \mathrm{ms} \pm 58.1 \mathrm{μs}\left({\color{gray}3.23 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	10 entities	$$14.6 \mathrm{ms} \pm 62.6 \mathrm{μs}\left({\color{gray}0.559 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	100 entities	$$14.5 \mathrm{ms} \pm 82.6 \mathrm{μs}\left({\color{gray}0.024 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	1000 entities	$$15.1 \mathrm{ms} \pm 77.2 \mathrm{μs}\left({\color{gray}-0.198 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	10000 entities	$$22.1 \mathrm{ms} \pm 121 \mathrm{μs}\left({\color{gray}-0.655 \mathrm{\%}}\right) $$	Flame Graph

representative_read_entity

Function	Value	Mean	Flame graphs
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/block/v/1	$$29.6 \mathrm{ms} \pm 298 \mathrm{μs}\left({\color{gray}-2.577 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/book/v/1	$$29.7 \mathrm{ms} \pm 271 \mathrm{μs}\left({\color{gray}4.90 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/building/v/1	$$29.2 \mathrm{ms} \pm 255 \mathrm{μs}\left({\color{gray}0.038 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/organization/v/1	$$28.4 \mathrm{ms} \pm 263 \mathrm{μs}\left({\color{gray}-3.778 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/page/v/2	$$29.8 \mathrm{ms} \pm 304 \mathrm{μs}\left({\color{gray}0.020 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/person/v/1	$$29.7 \mathrm{ms} \pm 277 \mathrm{μs}\left({\color{gray}4.56 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/playlist/v/1	$$29.2 \mathrm{ms} \pm 264 \mathrm{μs}\left({\color{gray}-1.699 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/song/v/1	$$30.0 \mathrm{ms} \pm 262 \mathrm{μs}\left({\color{gray}1.39 \mathrm{\%}}\right) $$	Flame Graph
entity_by_id	entity type ID: https://blockprotocol.org/@alice/types/entity-type/uk-address/v/1	$$29.3 \mathrm{ms} \pm 269 \mathrm{μs}\left({\color{gray}-0.296 \mathrm{\%}}\right) $$	Flame Graph

representative_read_entity_type

Function	Value	Mean	Flame graphs
get_entity_type_by_id	Account ID: bf5a9ef5-dc3b-43cf-a291-6210c0321eba	$$7.92 \mathrm{ms} \pm 36.3 \mathrm{μs}\left({\color{gray}0.176 \mathrm{\%}}\right) $$	Flame Graph

representative_read_multiple_entities

Function	Value	Mean	Flame graphs
entity_by_property	traversal_paths=0	0	$$87.2 \mathrm{ms} \pm 415 \mathrm{μs}\left({\color{gray}-0.578 \mathrm{\%}}\right) $$
entity_by_property	traversal_paths=255	1,resolve_depths=inherit:1;values:255;properties:255;links:127;link_dests:126;type:true	$$137 \mathrm{ms} \pm 502 \mathrm{μs}\left({\color{gray}1.32 \mathrm{\%}}\right) $$
entity_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:0;properties:0;links:0;link_dests:0;type:false	$$93.6 \mathrm{ms} \pm 471 \mathrm{μs}\left({\color{gray}-0.746 \mathrm{\%}}\right) $$
entity_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:0;properties:0;links:1;link_dests:0;type:true	$$102 \mathrm{ms} \pm 587 \mathrm{μs}\left({\color{gray}-0.451 \mathrm{\%}}\right) $$
entity_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:0;properties:2;links:1;link_dests:0;type:true	$$111 \mathrm{ms} \pm 516 \mathrm{μs}\left({\color{gray}0.182 \mathrm{\%}}\right) $$
entity_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:2;properties:2;links:1;link_dests:0;type:true	$$118 \mathrm{ms} \pm 632 \mathrm{μs}\left({\color{gray}0.079 \mathrm{\%}}\right) $$
link_by_source_by_property	traversal_paths=0	0	$$86.0 \mathrm{ms} \pm 448 \mathrm{μs}\left({\color{gray}0.528 \mathrm{\%}}\right) $$
link_by_source_by_property	traversal_paths=255	1,resolve_depths=inherit:1;values:255;properties:255;links:127;link_dests:126;type:true	$$113 \mathrm{ms} \pm 551 \mathrm{μs}\left({\color{gray}1.10 \mathrm{\%}}\right) $$
link_by_source_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:0;properties:0;links:0;link_dests:0;type:false	$$92.9 \mathrm{ms} \pm 472 \mathrm{μs}\left({\color{gray}0.408 \mathrm{\%}}\right) $$
link_by_source_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:0;properties:0;links:1;link_dests:0;type:true	$$99.8 \mathrm{ms} \pm 418 \mathrm{μs}\left({\color{gray}-0.566 \mathrm{\%}}\right) $$
link_by_source_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:0;properties:2;links:1;link_dests:0;type:true	$$102 \mathrm{ms} \pm 450 \mathrm{μs}\left({\color{gray}-0.140 \mathrm{\%}}\right) $$
link_by_source_by_property	traversal_paths=2	1,resolve_depths=inherit:0;values:2;properties:2;links:1;link_dests:0;type:true	$$103 \mathrm{ms} \pm 478 \mathrm{μs}\left({\color{gray}0.958 \mathrm{\%}}\right) $$

scenarios

Function	Value	Mean	Flame graphs
full_test	query-limited	$$139 \mathrm{ms} \pm 628 \mathrm{μs}\left({\color{red}5.58 \mathrm{\%}}\right) $$	Flame Graph
full_test	query-unlimited	$$136 \mathrm{ms} \pm 376 \mathrm{μs}\left({\color{red}5.36 \mathrm{\%}}\right) $$	Flame Graph
linked_queries	query-limited	$$102 \mathrm{ms} \pm 576 \mathrm{μs}\left({\color{red}27.3 \mathrm{\%}}\right) $$	Flame Graph
linked_queries	query-unlimited	$$574 \mathrm{ms} \pm 1.10 \mathrm{ms}\left({\color{gray}2.63 \mathrm{\%}}\right) $$	Flame Graph