Introduce EqualElementTypesOpTrait to replace manual element type verification by Copilot · Pull Request #933 · iree-org/wave

Copilot · 2026-02-19T23:40:32Z

Summary

This PR introduces a new EqualElementTypesOpTrait to replace manual element type verification in Wave operations. The trait verifies that all operands and results of an operation have the same element type.

Changes Made

New Trait Implementation:
- Defined in WaveInterfaces.td
- Implemented in WaveInterfaces.h and WaveInterfaces.cpp
- Efficiently compares all operands and results against a reference type
- Uses traditional for loops to iterate over operands/results
- Uses llvm::StringRef for string storage (LLVM best practice)
- Uses llvm::Twine for string concatenation (LLVM best practice)
Applied to Operations:
- RegisterOp: Verifies scalar init type matches tensor/vector element type
- ExtractOp: Verifies source and result element types match
- BroadcastOp: Verifies source and result element types match
- PermuteOp: Verifies input and result element types match
Removed Manual Verification:
- Eliminated duplicate verification code from 4 operations
- Centralized logic in the trait
Updated Tests:
- Modified test expectations to match generic trait error messages
- Added negative test for ExtractOp element type mismatch

Original prompt

This section details on the original issue you should resolve

<issue_title>Minor cleanup: introduce a trait for equal element types</issue_title>
<issue_description>We want this in most operations and are currently verifying manually in a subset, use a trait instead.</issue_description>

<agent_instructions>Look at the WaveInterfaces.td file to find examples of other traits. They are related to C++ classes in WaveInterfaces.h</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes Minor cleanup: introduce a trait for equal element types #805

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

…muteOp, and RegisterOp Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

ftynse · 2026-02-20T08:14:56Z

@copilot there's a build error, please fix

Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Copilot · 2026-02-20T08:17:11Z

@copilot there's a build error, please fix

Fixed in 52a3478. The build error was caused by using std::to_string which isn't available in the MLIR build environment. Replaced with llvm::Twine which is the standard LLVM approach for string concatenation with numbers.

ftynse · 2026-02-20T09:26:08Z

@copilot there is still a build failure: /home/runner/_work/wave/wave/water/lib/Dialect/Wave/IR/WaveInterfaces.cpp:722:45: error: no member named 'drop_front' in 'mlir::ValueTypeRange<mlir::ResultRange>' please fix

…alueTypeRange Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Copilot · 2026-02-20T09:27:32Z

@copilot there is still a build failure: `/home/runner/_work/wave/wave/water/lib/Dialect/Wave/IR/WaveInterfaces.cpp:722:45: error: no member named 'drop_front' in 'mlir::ValueTypeRange<mlir::ResultRan...

Fixed in 05744cf. The mlir::ValueTypeRange returned by getOperandTypes() and getResultTypes() doesn't have a drop_front() method. Replaced with traditional for loops that start from the appropriate index.

Signed-off-by: Alex Zinenko <git@ozinenko.com>

martin-luecke

LGTM,
just a nit and a missing test.
@copilot pls fix

martin-luecke · 2026-02-20T13:47:24Z

water/lib/Dialect/Wave/IR/WaveInterfaces.cpp

+  // Get the reference type from the first operand if available, otherwise from
+  // the first result
+  Type referenceType;
+  std::string referenceName;


@copilot Use LLVM data stuctures where possible. This should probably be StringRef and std::to_string is also not idiomatic LLVM

Fixed in 0b07423. Changed std::string referenceName to llvm::StringRef referenceName and replaced std::to_string with llvm::Twine.

martin-luecke · 2026-02-20T13:48:06Z

water/test/Dialect/Wave/ops-invalid.mlir

@@ -843,7 +843,7 @@ func.func @broadcast_explicit_dims_with_fully_specified_types(%arg0: !wave.tenso

 func.func @broadcast_element_type_mismatch(%arg0: !wave.tensor<[@M, @N] of f32, <register>>) {


@copilot Please also a negative test for ExtractOp, where the trait was added as well.

Added in 0b07423. Added test extract_element_type_mismatch that verifies the trait catches element type mismatches between source and result.

- Changed std::string to llvm::StringRef for referenceName - Changed std::to_string to llvm::Twine for string concatenation - Added negative test for ExtractOp element type mismatch Co-authored-by: martin-luecke <16363540+martin-luecke@users.noreply.github.com>

Copilot · 2026-02-20T13:50:45Z

LGTM,
just a nit and a missing test.
@copilot pls fix

Fixed in 0b07423. Changed to use llvm::StringRef and llvm::Twine, and added negative test for ExtractOp.

Initial plan

c8f68cf

Copilot AI assigned Copilot and ftynse Feb 19, 2026

Copilot started work on behalf of ftynse February 19, 2026 23:40 View session

Copilot AI and others added 4 commits February 19, 2026 23:45

Add EqualElementTypesOpTrait and apply to ExtractOp, BroadcastOp, Per…

219e255

…muteOp, and RegisterOp Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Update test expectations for new EqualElementTypesOpTrait error messages

2031756

Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Address code review: avoid redundant element type checks

a3728ee

Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Final verification and documentation

4fa1051

Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Introduce trait for equal element types in operations~~ Introduce EqualElementTypesOpTrait to replace manual element type verification Feb 19, 2026

Copilot AI requested a review from ftynse February 19, 2026 23:54

Copilot finished work on behalf of ftynse February 19, 2026 23:54

Copilot started work on behalf of ftynse February 20, 2026 08:15 View session

Fix build error: use llvm::Twine instead of std::to_string

52a3478

Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Copilot finished work on behalf of ftynse February 20, 2026 08:17

Copilot started work on behalf of ftynse February 20, 2026 09:26 View session

Fix build error: use traditional for loops instead of drop_front on V…

05744cf

…alueTypeRange Co-authored-by: ftynse <1512299+ftynse@users.noreply.github.com>

Copilot finished work on behalf of ftynse February 20, 2026 09:28

ftynse added 2 commits February 20, 2026 14:16

don't use it for register

ee783f3

Signed-off-by: Alex Zinenko <git@ozinenko.com>

drop artefact

d66de9e

Signed-off-by: Alex Zinenko <git@ozinenko.com>

ftynse approved these changes Feb 20, 2026

View reviewed changes

ftynse marked this pull request as ready for review February 20, 2026 13:17

ftynse requested a review from martin-luecke February 20, 2026 13:17

martin-luecke approved these changes Feb 20, 2026

View reviewed changes

Copilot started work on behalf of martin-luecke February 20, 2026 13:48 View session

Copilot finished work on behalf of martin-luecke February 20, 2026 13:51

Copilot AI requested a review from martin-luecke February 20, 2026 13:51

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Introduce EqualElementTypesOpTrait to replace manual element type verification#933

Introduce EqualElementTypesOpTrait to replace manual element type verification#933
Copilot wants to merge 10 commits intomainfrom
copilot/introduce-equal-element-types-trait

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		@@ -843,7 +843,7 @@ func.func @broadcast_explicit_dims_with_fully_specified_types(%arg0: !wave.tenso

		func.func @broadcast_element_type_mismatch(%arg0: !wave.tensor<[@M, @N] of f32, <register>>) {

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Copilot AI commented Feb 19, 2026 •

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