DIP56 Provide pragma to control function inlining

[Francesco Cattoglio]

On Sunday, 23 February 2014 at 20:40:44 UTC, Walter Bright wrote:
> Generally, when I optimize at that level, I have a window open 
> on the assembler output of the compiler and I go back and forth 
> on the source code until I get the shape of the assembler I 
> need. Having compiler messages wouldn't be very helpful.

Not everyone has time/knowledge for checking the ASM at every 
recompile. Personally I wouldn't be able to do something like 
this that much often, and yet I'd love to know that something is 
not working ASAP.

Code changes, and it changes a lot during development. Having a 
way to make sure that one or more functions stay inlined is handy 
to have. If such a pragma doesn't guarantee inlining, that means 
we will have no way to check it quickly. Sometimes fail fast is 
really the best choice.