[LLVMdev] LLVM frontend supporting arbitrary bit-width integral datatypes

[ihusar]

Hello gyus,

I am working on a project, where we are trying to create a development environment 
for new ASIP processor design. Part of this project is a compiler generator, 
where we would like to generate C compiler from some instruction description. 

To keep it short, let's say, that in each instruction's semantics
is described by some C code. What I would like to do is to compile this code with LLVM, 
let it optimize it and then extract instruction selection rules for each instruction (either from LLVM IR
or from created code selection DAG).
Then, I will use these selection rules and some additional information about registers etc. to generate 
LLVM compiler backend for the designed ASIP.

First, I would like to ask, whether you heard about some proects, where they are also trying to generate LLVM backends.
(any related information would be useful)

Second, in the code, that describes instruction's semantics, I need to use some special datatypes 
like 5-bit wide unsigned integer and similar. I heard about some Embedded C extension for the CGG frontend, 
but I have not found anything about it yet. Or, does the CLang support such datatypes?

Have a nice day and thanks in advance
  Adam