compiler: handle set-and-use-temp in nilcheck code

Change the code in Unary_expression::do_get_backend that introduces
explicit nil checks for dereference operations to special case
set-and-use-temporary expressions. For this case it is better to
generate an explicit reference of the temp in the final conditional
(avoids introducing tree sharing).

Change-Id: Ic7d83605d93212af36ef8f069ffbb080e9697db8
Reviewed-on: https://go-review.googlesource.com/81915
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed