# Copyright (c) 2017 Chris Seaton
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

module Rhizome
  module Passes

    # A pass to replace parts of the graph with a canonical representation so
    # that other phases can look for just that representation.

    class Canonicalise

      def run(graph)
        modified = false

        # Look at each node.

        graph.all_nodes.each do |n|
          # Replace not(int64_not_zero?) with int64_zero?

          if n.op == :not && n.inputs.from_node.op == :int64_not_zero?
            IR::Node.replace_multiple n.inputs.from_node, n, IR::Node.new(:int64_zero?)
          end
        end

        modified
      end

    end

  end
end
