zig/doc/langref/float_mode_obj.zig

const std = @import("std");
const big = @as(f64, 1 << 40);

export fn foo_strict(x: f64) f64 {
    return x + big - big;
}

export fn foo_optimized(x: f64) f64 {
    @setFloatMode(.optimized);
    return x + big - big;
}

// obj
// optimize=ReleaseFast
// disable_cache