Struct FpuGuard 

pub struct FpuGuard { /* private fields */ }

RAII guard that protects a computation from dangerous FPU settings

On creation:

1. Triggers one-time FPU check and warning (if not already done)
2. If FZ or DAZ is enabled, disables them temporarily

On drop:

• Restores the original FPU state

Example

use sparse_ir::fpu_check::{FpuGuard, get_fpu_state};

let before = get_fpu_state();
{
    let _guard = FpuGuard::new_protect_computation();
    // Computation here - FZ/DAZ are disabled
    assert!(!get_fpu_state().is_dangerous());
    let subnormal = std::hint::black_box(f64::MIN_POSITIVE) / 2.0;
    assert!(subnormal > 0.0); // not flushed to zero
} // Original FPU state is restored here
let after = get_fpu_state();
assert_eq!(after.flush_to_zero, before.flush_to_zero);
assert_eq!(after.denormals_are_zero, before.denormals_are_zero);

Performance

The overhead is negligible (a few CPU cycles for stmxcsr/ldmxcsr).

Implementations

impl FpuGuard

pub fn new_protect_computation() -> Self

Create a new guard that protects computation from FZ/DAZ

• Triggers one-time warning if dangerous FPU settings are detected
• Temporarily disables FZ/DAZ if they are enabled
• Restores original state when dropped

pub fn was_modified(&self) -> bool

Check if the guard needed to modify FPU state

Trait Implementations

impl Drop for FpuGuard

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.