February 2026 Monthly Summary for golang/go focusing on Zicond RISC-V Code Generation Optimization. Implemented targeted code generation improvements for the Zicond extension on riscv64, optimizing branch handling to boost performance on unpredictable branches while mitigating regressions on predictable branches. Introduced a selective enablement of CondSelect: globally disabled for riscv64 and enabled only for the ConstantTimeSelect intrinsic, which benefits most from Zicond. This approach preserves safety and performance balance across crypto-sensitive paths. Key changes include: 1) added codegen for Zicond extension on riscv64; 2) reformulated branches to CondSelect where beneficial, with safeguards to avoid regressions; 3) performance benchmarking showing notable gains in ConstantTimeSelect, with approximately 24.69% improvement in sec/op (ConstantTimeSelect-44 went from 2.325ns to 1.750ns; p=0.000, n=10). The patch documents the change, including Change-Id and PR references. Impact: Improves crypto-subtle performance while preserving baseline behavior for predictable branches; aligns with RVA23u64 requirement and Go’s crypto Subtle optimization goals. The commit was authored with collaboration (co-authored-by) and contributed under golang/go#75577 with reviews from Go maintainers. Commit reference included: ca94cf12479f2a2c065215218f6a3f5fc7bfe1f4.

Month: 2025-11 — Delivered Zbc extension carry-less multiplication support for Go on RISC-V. Implemented assembly support for carry-less multiply instructions (clmul, clmulh, clmulr) to accelerate polynomial arithmetic over GF(2) used in cryptography and error-correcting codes. The change landed in the RISC-V path (cmd/internal/obj/riscv) with focused code review and documentation updates. No major bugs fixed this month; activities centered on delivering a robust hardware-accelerated path and ensuring correctness across architectures. Business value: improved cryptographic throughput and ECC performance on affected platforms, strengthened the Go cryptography stack through hardware-assisted operations.

Monthly work summary for golang/arch - 2025-10: Delivered RISC-V Zicond extension support for 64-bit architecture by updating the assembler's instruction tables and test data to correctly disassemble and recognize Zicond instructions. This aligns the project with newer RISC-V specifications and improves toolchain compatibility for downstream users.

September 2025 focused on expanding Go's RISC-V backend capabilities by adding Zicond Extension Assembler Support (CZEROEQZ and CZERONEZ). The change enhances integer conditional operations and broadens hardware support for code generation in the Go assembly path.