Month: 2026-06 — Summary: In June, the CIRCT team delivered and stabilized a set of critical Verilog import and LLHD transformation improvements that directly enhance interoperability, reliability, and performance for downstream toolchains and testbenches. Notable advances include a comprehensive set of Verilog import and interoperability enhancements, performance-oriented improvements to function splitting, and stability fixes in control-flow rewrites that reduce downstream failures during region lowering. The work accelerates adoption by customers and internal teams relying on accurate, faster Verilog import, DPI-C interoperability, and scalable MLIR transformations.

April 2026 (2026-04) monthly summary for llvm/circt focused on delivering Verilog interface enhancements with robust test coverage to improve integration and correctness. The main feature delivered enables hierarchical access to interface members and supports return statements in procedures and tasks, strengthening interoperability with existing structures and downstream workflows. This work included tests to validate correctness and compatibility, reducing the risk of regressions in Verilog import. No distinct bug fixes were logged this month; value came from feature delivery, tests, and improved maintainability. Business value: smoother Verilog integration, more expressive interface usage, and lower maintenance cost through tests and verification. Technologies/skills demonstrated include Verilog/SystemVerilog semantics, hierarchical access patterns, ImportVerilog tooling, test-driven development, and collaboration on issue #10095.

In March 2026, delivered the feature to lower SystemVerilog virtual interfaces into Moore IR for OpenXiangShan/circt, enabling member access and supporting modports and typedefs. The approach represents virtual interface handles as ustruct-of-ref fields and materializes assignments from concrete interface instances, paving the way for realistic UVM-style verification flows. Added tests to cover typical virtual interface flows and included a small naming fix to align with Moore IR conventions. No major bug fixes this month; the focus was on feature delivery, test coverage, and preparing downstream IR consumers for enhanced modeling fidelity.