Function mark_cold

crates/codegen/src/ir.rs:2102–2140

flowgraph.c mark_cold

(blocks: &mut [Block])

/// flowgraph.c mark_cold
fn mark_cold(blocks: &mut [Block]) {
    let n = blocks.len();
    let mut warm = vec![false; n];
    let mut queue = VecDeque::new();

    warm[0] = true;
    queue.push_back(BlockIdx(0));

    while let Some(block_idx) = queue.pop_front() {
        let block = &blocks[block_idx.idx()];

        let has_fallthrough = block
            .instructions
            .last()
            .map(|ins| !ins.instr.is_scope_exit() && !ins.instr.is_unconditional_jump())
            .unwrap_or(true);
        if has_fallthrough && block.next != BlockIdx::NULL {
            let next_idx = block.next.idx();
            if !blocks[next_idx].except_handler && !warm[next_idx] {
                warm[next_idx] = true;
                queue.push_back(block.next);
            }
        }

        for instr in &block.instructions {
            if instr.target != BlockIdx::NULL {
                let target_idx = instr.target.idx();
                if !blocks[target_idx].except_handler && !warm[target_idx] {
                    warm[target_idx] = true;
                    queue.push_back(instr.target);
                }
            }
        }
    }

    for (i, block) in blocks.iter_mut().enumerate() {
        block.cold = !warm[i];
    }
}

/// flowgraph.c push_cold_blocks_to_end
fn push_cold_blocks_to_end(blocks: &mut Vec<Block>) {