perf: enable partial function call and static memory read by letypequividelespoubelles · Pull Request #2191 · LFDT-Lineth/zkc

letypequividelespoubelles · 2026-08-26T04:02:29Z

No description provided.

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

Copilot

Pull request overview

This PR adds first-class support for partial bindings in ZkC (using _ to discard selected return values) across the compiler, VM bytecode/encoding, and constraint emission, and includes new fixtures/tests to validate the behavior for both function calls and static-memory reads.

Changes:

Introduces a discardable assignment target (_) via a new lval.Discard AST node and threads it through parsing, typing, linking, lowering, and codegen using a DISCARD pseudo-register.
Updates VM transforms, interpreter encoding, gogen, and constraint lookup emission to correctly handle discarded call returns and discarded static-memory data columns.
Adds unit/invalid fixtures and Go tests covering partial-call patterns and rejecting illegal _ usage.

Reviewed changes

Copilot reviewed 43 out of 43 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
testdata/zkc/unit/partial_call_01.zkc	Unit fixture: discard second return in a 2-tuple function call.
testdata/zkc/unit/partial_call_01.accepts	Accepted traces for partial_call_01.
testdata/zkc/unit/partial_call_02.zkc	Unit fixture: discard first return in a 2-tuple function call.
testdata/zkc/unit/partial_call_02.accepts	Accepted traces for partial_call_02.
testdata/zkc/unit/partial_call_03.zkc	Unit fixture: discard first/third returns in a 3-tuple function call.
testdata/zkc/unit/partial_call_03.accepts	Accepted traces for partial_call_03.
testdata/zkc/unit/partial_call_04.zkc	Unit fixture: discard middle return in a 3-tuple function call.
testdata/zkc/unit/partial_call_04.accepts	Accepted traces for partial_call_04.
testdata/zkc/unit/partial_call_05.zkc	Unit fixture: discard one column from a multi-column static memory read.
testdata/zkc/unit/partial_call_05.accepts	Accepted traces for partial_call_05.
testdata/zkc/invalid/partial_call_01.zkc	Invalid fixture: rejects discarding all returns in an assignment.
testdata/zkc/invalid/partial_call_02.zkc	Invalid fixture: mismatched return arity (too few targets).
testdata/zkc/invalid/partial_call_03.zkc	Invalid fixture: mismatched return arity (too many targets).
testdata/zkc/invalid/basic_42.zkc	Invalid fixture: rejects declaring `_` as a variable.
testdata/zkc/invalid/basic_43.zkc	Invalid fixture: rejects calling a function named `_`.
testdata/zkc/invalid/basic_44.zkc	Invalid fixture: rejects reading from `_` as an identifier.
testdata/zkc/invalid/basic_45.zkc	Invalid fixture: rejects declaring a function named `_`.
pkg/zkc/vm/internal/transform/split_registers.go	Keeps call boundaries aligned when returns are discarded during register splitting.
pkg/zkc/vm/internal/transform/lower_shift.go	Refactors shift helper construction (builder) to better control registers/temps.
pkg/zkc/vm/internal/transform/lower_or_xor_and.go	Merges AND/OR/XOR helpers into a single multi-output helper; supports discarding unused outputs.
pkg/zkc/vm/internal/transform/inline_functions.go	Ensures inlining/shadow-mapping logic treats discarded returns as unbound.
pkg/zkc/vm/internal/transform/check_casts.go	Skips cast checks for discarded return bindings.
pkg/zkc/vm/internal/interpreter/encoding/readwrite.go	Densifies static-read data bindings so positional executors bind remaining lines correctly.
pkg/zkc/vm/internal/interpreter/encoding/call.go	Densifies call return bindings for LEAVE encoding; adds denseBindings helper.
pkg/zkc/vm/internal/gogen/emit_memory.go	Skips loads for discarded static memory data lines.
pkg/zkc/vm/internal/gogen/emit_call.go	Emits blanks in Go tuple assignments for discarded returns.
pkg/zkc/vm/internal/bytecode/util.go	Renders DISCARD as `_` and adds boundRegisters helper to filter discards.
pkg/zkc/vm/internal/bytecode/readwrite.go	Excludes discarded read data from Definitions; validates discards only allowed on read data.
pkg/zkc/vm/internal/bytecode/call.go	Excludes discarded returns from Definitions; validates discards only allowed on returns.
pkg/zkc/vm/internal/bytecode/bytecode.go	Introduces `DISCARD` pseudo register id and updates operand validation accordingly.
pkg/zkc/vm/bytecode.go	Re-exports `DISCARD` for external VM consumers.
pkg/zkc/constraints/translator.go	Computes padded static height from row count (StaticHeight) rather than flattened contents length.
pkg/zkc/constraints/call_and_memory_lookup.go	Omits discarded (source,target) pairs from call/memory lookup constraints.
pkg/zkc/compiler/validate/typing.go	Adds dedicated typing path for assignments with discarded targets (`_`).
pkg/zkc/compiler/parser/parser.go	Reserves `_` for discard targets; rejects it for declarations and reads.
pkg/zkc/compiler/lower/flatten_fixed_array.go	Preserves discard lvals during fixed-array lowering.
pkg/zkc/compiler/linker.go	Links discard lvals into resolved AST.
pkg/zkc/compiler/codegen/statement.go	Maps discard lvals to the DISCARD pseudo-register; clarifies destructuring behavior.
pkg/zkc/compiler/codegen/compile.go	Flattens tuple static initializers row-major to support multi-column static memories.
pkg/zkc/compiler/ast/lval/lval.go	Adds stringification support for discard lvals.
pkg/zkc/compiler/ast/lval/discard.go	Introduces the discard lval node (`lval.Discard`).
pkg/test/zkc_unit_test.go	Registers new unit tests for partial-call/static-read discard behavior.
pkg/test/zkc_invalid_test.go	Registers new invalid tests for `_`-related parse/typing failures.

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+// This test perform a partial call res, _ = f(x)
+func Test_ZkcUnit_partial_call_01(t *testing.T) {
+	checkZkcUnit(t, "zkc/unit/partial_call_01", DEFAULT_UNIT_CONFIG)
+}


+// ===================================================================
+// Unreachable module from main
+// ===================================================================
+func Test_ZkcInvalid_Partial_call_01(t *testing.T) {
+	checkZkcInvalid(t, "zkc/invalid/partial_call_01")
+}


 		mask     = (uint64(1) << width) - 1
 		rows     = uint64(1) << (2 * width)
-		contents = make([]W, rows)
+		contents = make([]W, 0, rows*uint64(len(bitwiseOps)))


Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

Copilot

Pull request overview

Copilot reviewed 44 out of 44 changed files in this pull request and generated 1 comment.

Suppressed comments (5)

pkg/test/zkc_unit_test.go:1451

Grammar: “This test performs …” (subject–verb agreement).

// This test perform a partial call res, _ = f(x)

pkg/test/zkc_unit_test.go:1456

Grammar: “This test performs …” (subject–verb agreement).

// This test perform a partial call _, res = f(x)

pkg/test/zkc_unit_test.go:1461

Grammar: “This test performs …” (subject–verb agreement).

// This test perform a partial call _, res, _ = f(x)

pkg/test/zkc_unit_test.go:1466

Grammar: “This test performs …” (subject–verb agreement).

// This test perform a partial call res, _, res = f(x)

pkg/test/zkc_unit_test.go:1471

Grammar: “This test performs …” (subject–verb agreement).

// This test perform a partial static call res, _ = static(x)

DavePearce

Overall, I think this looks pretty good. I have requested some changes, but they are mostly pretty minor.

DavePearce · 2026-08-27T00:57:32Z

+	}
+	// Sanity check at least one return value is bound
+	if !array.ContainsMatching(s.Targets, func(lv LVal) bool { return !isDiscard(lv) }) {
+		return p.srcmaps.SyntaxErrors(s, "at least one return argument must be used")


Why enforce this requirement? Its not necessary.

It's not necessary, but I see it as a "garde-fou". I don't see any use case where we would like _ = f(x)

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

DavePearce

Overall, looks good. The change merging typePartialAssignment() into typeAssignment was not done well, but otherwise looks good.

DavePearce · 2026-08-31T21:55:48Z

+	// Partial assignment: one or more targets are the wildcard "_".
+	// Discarding is only meaningful for sources whose return types are fixed by
+	// a declaration (function calls and static memory reads).
+	if array.ContainsMatching(s.Targets, isDiscard) {


Oh, I love this so much. I can only hope that Claude is solely responsible ;)

letypequividelespoubelles added 2 commits August 25, 2026 17:11

perf: enable partial call and static memory read

59e4d77

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

use it for and/or/xor

450ec94

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

Copilot AI lite review requested due to automatic review settings August 26, 2026 04:02

letypequividelespoubelles self-assigned this Aug 26, 2026

Copilot started reviewing on behalf of letypequividelespoubelles August 26, 2026 04:03 View session

letypequividelespoubelles changed the title ~~Perf enable partial fct call~~ perf: enable partial function and static memory call Aug 26, 2026

letypequividelespoubelles changed the title ~~perf: enable partial function and static memory call~~ perf: enable partial function call and static memory read Aug 26, 2026

Copilot AI reviewed Aug 26, 2026

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letypequividelespoubelles and others added 2 commits August 26, 2026 10:02

add invalid test with RAM

6323c53

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

Merge branch 'main' into perf-enable-partial-fct-call

d0af9f4

letypequividelespoubelles requested a lite review from Copilot August 26, 2026 04:35

Copilot started reviewing on behalf of letypequividelespoubelles August 26, 2026 04:35 View session

Copilot AI reviewed Aug 26, 2026

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Comment thread pkg/zkc/vm/internal/transform/lower_or_xor_and.go Outdated

letypequividelespoubelles mentioned this pull request Aug 26, 2026

feat: reduce number of lowered shift modules #2187

Open

letypequividelespoubelles linked an issue Aug 26, 2026 that may be closed by this pull request

enable partial function call #2010

Closed

Merge branch 'main' into perf-enable-partial-fct-call

ffc307a

DavePearce requested changes Aug 27, 2026

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letypequividelespoubelles added 3 commits August 31, 2026 19:38

ras rebase

2c51120

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

dave's review

1103dba

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

ras

73adb7b

Signed-off-by: F Bojarski <ceciestunepoubelle@protonmail.ch>

letypequividelespoubelles enabled auto-merge (squash) August 31, 2026 15:03

DavePearce approved these changes Aug 31, 2026

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letypequividelespoubelles merged commit a25298f into main Aug 31, 2026
22 checks passed

letypequividelespoubelles deleted the perf-enable-partial-fct-call branch August 31, 2026 22:03

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perf: enable partial function call and static memory read - #2191

perf: enable partial function call and static memory read#2191
letypequividelespoubelles merged 8 commits into
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letypequividelespoubelles commented Aug 26, 2026

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