It's spelled "ins", not "in".

ir/be/amd64/amd64_spec.pl

@@ -173,7 +173,7 @@ Add => {
 	state      => "exc_pinned",
 	reg_req    => { in => [ "gp", "gp" ],
 	                out => [ "gp" ] },
-	in         => [ "left", "right" ],
+	ins        => [ "left", "right" ],
 	outs       => [ "res" ],
 	mode       => $mode_gp,
 	modified_flags => 1,
@@ -198,7 +198,7 @@ Sub => {
 	state      => "exc_pinned",
 	reg_req    => { in => [ "gp", "gp" ],
 	                out => [ "gp" ] },
-	in         => [ "left", "right" ],
+	ins        => [ "left", "right" ],
 	outs       => [ "res" ],
 	mode       => $mode_gp,
 	modified_flags => 1,