RISC-V no-panic (part 2)

[nazar-pc]

More things were already panic-free, just needed a higher inlining limits. Others required minor changes and clarifications to nudge compiler towards the correct conclusion.

[Copilot]

Pull request overview

This PR continues the effort to make the RISC-V vector interpreter codebase no-panic compatible by removing panicking paths (e.g., expect) and adding no_panic annotations, plus a CI tweak to allow more inlining for the analysis to succeed.

Changes:

• Replace some expect(...)-based invariants with unwrap_unchecked() guarded by explicit safety comments in widen/narrow helpers.
• Add #[cfg_attr(feature = "no-panic", no_panic_const::no_panic)] to a number of vector helper entrypoints that previously had TODO markers.
• Refactor mul/div helpers to use widening_mul and wrapping_{div,rem}; increase CI inline threshold for the no-panic job.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
crates/execution/ab-riscv-interpreter/src/v/zvexx/widen_narrow/zvexx_widen_narrow_helpers.rs	Switch sign-extension helpers to take Vsew; remove expect in favor of unwrap_unchecked; add no_panic attribute to execute helpers.
crates/execution/ab-riscv-interpreter/src/v/zvexx/widen_narrow.rs	Update callers to new sign_extend_bits signature (notably XLEN scalar handling).
crates/execution/ab-riscv-interpreter/src/v/zvexx/store/zvexx_store_helpers.rs	Add no_panic attribute to store execute helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/reduction/zvexx_reduction_helpers.rs	Add no_panic attribute to reduction execute helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/perm/zvexx_perm_helpers.rs	Add no_panic attribute to permute/slide/merge/compress helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/muldiv/zvexx_muldiv_helpers.rs	Refactor multiply-high/div/rem helpers to reduce panic potential and use widening ops; add no_panic attributes.
crates/execution/ab-riscv-interpreter/src/v/zvexx/mask/zvexx_mask_helpers.rs	Add no_panic attribute to mask helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/load/zvexx_load_helpers.rs	Add no_panic attribute to load helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/fixed_point/zvexx_fixed_point_helpers.rs	Add no_panic attribute to fixed-point helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/config/zvexx_config_helpers.rs	Add no_panic attribute to vsetvl/vsetivli config helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/carry/zvexx_carry_helpers.rs	Add no_panic attribute to carry/borrow helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/v/zvexx/arith/zvexx_arith_helpers.rs	Add no_panic attribute to arithmetic/compare helpers (replacing TODO markers).
crates/execution/ab-riscv-interpreter/src/lib.rs	Enable the widening_mul nightly feature gate.
crates/execution/ab-riscv-interpreter/Cargo.toml	Update feature-notes comment (removing now-addressed TODO item).
.github/workflows/rust.yml	Increase LLVM inline threshold for the no-panic check job.

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[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

crates/execution/ab-riscv-primitives/src/instructions/v.rs:515

• Vsew::from_xlen is annotated with #[cfg_attr(feature = "no-panic", no_panic_const::no_panic)] but still contains a panic!() path. Because Reg::XLEN is not statically proven to be only 32/64 for all Register impls, this will likely fail the no-panic check (and contradicts the goal of the PR). Consider making the “impossible” arm panic-free under feature="no-panic" (while keeping a panic in normal builds).

                64 => Self::E64,
                _ => {
                    // TODO: Should have been `unreachable!()`:
                    //  https://github.com/rust-lang/rust/issues/159645
                    panic!("Invalid register width")

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 4 comments.