To enable optimizations that perform automatic inlining, use /optimize:4 (or /optimize:5). Using /optimize:4 also enables local optimizations (/optimize:1), global optimizations (/optimize:2), and additional global optimizations (/optimize:3).
To request inlining at lower optimization levels (/optimize:1, /optimize:2, or /optimize:3), use the /inline option.
The default is /optimize:4 (unless /debug is specified), except in the visual development environment for a debug configuration.