Implement opt_share

This pass identifies arithmetic operators that share an operand and whose
results are used in mutually exclusive cases controlled by a multiplexer, and
merges them together by multiplexing the other operands

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/opt/opt_share_mux_tree.v b/tests/opt/opt_share_mux_tree.v
new file mode 100644
index 000000000..807ed2978
--- /dev/null
+++ b/tests/opt/opt_share_mux_tree.v
@@ -0,0 +1,19 @@
+module add_sub(
+               input [15:0] 		 a,
+               input [15:0] 		 b,
+               input [15:0] 		 c,
+               input [1:0] 			 sel,
+               output reg [15:0] res
+               );
+
+
+  always @* begin
+    case(sel)
+      0: res = a + b;
+      1: res = a - b;
+      2: res = a + c;
+      default: res = 16'bx;
+    endcase
+  end
+
+endmodule