Method block_dominates

cranelift/codegen/src/dominator_tree/simple.rs:153–167

Returns `true` if `block_a` dominates `block_b`. A block is considered to dominate itself.

(&self, block_a: Block, mut block_b: Block)

    ///
    /// A block is considered to dominate itself.
    fn block_dominates(&self, block_a: Block, mut block_b: Block) -> bool {
        let rpo_a = self.nodes[block_a].rpo_number;

        // Run a finger up the dominator tree from b until we see a.
        // Do nothing if b is unreachable.
        while rpo_a < self.nodes[block_b].rpo_number {
            let idom = match self.idom(block_b) {
                Some(idom) => idom,
                None => return false, // a is unreachable, so we climbed past the entry
            };
            block_b = idom;
        }

        block_a == block_b
    }

    /// Compute the common dominator of two basic blocks.
    ///