rtl understanding till what level?

[Bryce McKinlay]

rashmi kankaria wrote:

>if one is given a task of writing a front end of gcc like the existing frontend for cpp(typically till creation of ast with managing other things ofcourse ..) then how much knowledge of rtl is required?
>

None. All communication between a front-end and the back-end is via the 
AST ("tree"), front-ends do not need to deal with RTL at all. However, 
some understanding of RTL can certainly help with debugging.

> does gcc documentation provides that much help or else needs to go thru the source files to really understand the rtl exprs..?
>

RTL seems to be fairly well documented in the GCC manual. The AST format 
is less well documented, mainly in tree.def, tree.h, and c-tree.texi for 
the C/C++ specific tree nodes. The front-end interface basically isn't 
documented at all, and is still more complex than it needs to be. All 
you can do is look at the other front-ends and do what they do.

regards

Bryce.