[mlir] Add tests for Support struct types in abi.encode/abi.decode lowering

[vladimirradosavljevic]

solx-llvm PR.

[Copilot]

Pull request overview

This PR expands the MLIR/EVM test suite to cover struct handling in abi.encode / abi.decode, and adds additional storage layout regression coverage around packed fixed arrays followed by scalar members.

Changes:

• Add new lit + semantic tests for struct abi.decode lowering, including nested structs and dynamic members.
• Add new semantic tests for struct abi.encode across memory/calldata and selected storage cases.
• Extend existing storage struct/array tests to exercise packed fixed-array edge cases (packed array field followed by scalar field, plus a following scalar to detect layout overlap).

Reviewed changes

Copilot reviewed 7 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/lit/mlirCodegen/storage-struct.sol	Extends MLIR “init” checks with a packed fixed-array-in-struct + tail scalar case, including guard/pad variables to detect layout overlap.
test/lit/mlirCodegen/EVM/storage-struct.sol	Extends EVM lowering checks for the same packed fixed-array + tail scalar storage layout scenario.
test/lit/mlirCodegen/EVM/storage-array.sol	Adds a scalar written from staticArr8[1] to validate packed fixed-array element access and subsequent scalar storage write in EVM lowering.
test/lit/mlirCodegen/EVM/abi-decode-struct.sol	New lit test file validating EVM lowering for struct ABI decode (memory + calldata, nested + dynamic members).
test/libsolidity/semanticTests/mlir/storage-struct.sol	Adds a semantic regression test for a packed fixed-array struct member followed by a scalar member in storage.
test/libsolidity/semanticTests/mlir/invalid-abi.sol	Extends invalid ABI semantic coverage to include invalid struct calldata/memory decoding/encoding paths.
test/libsolidity/semanticTests/mlir/abi-encode-struct.sol	New semantic test for abi.encode of structs in memory/calldata plus selected storage struct encoding cases.
test/libsolidity/semanticTests/mlir/abi-decode-struct.sol	New semantic test for struct ABI decode in memory/calldata, including nested/dynamic members.

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[abinavpp]

Thank you!