[LLVMdev] [RFC] Resurrecting the C back-end

[Cameron Zwarich]

On Aug 27, 2012, at 10:39 PM, Philipp Klaus Krause <pkk at spth.de> wrote:

> On 28.08.2012 14:08, Joshua Cranmer wrote:
>> On 8/27/2012 9:57 PM, Hongbin Zheng wrote:
>>> I think the C backend also allow people performing source-to-source
>>> transform with LLVM (instead of Clang).
>> 
>> I do not believe that this would be the case nor that it should be a
>> goal. Source-to-source transformation requires a lot of accurate
>> information about the AST, and conversion to LLVM IR is way too lossy.
>> Signedness, for example, is lost at IR generation, as is any pretense of
>> machine independence.
>> 
> 
> Why is it not possible to have the C backend emit machine-independent
> code (i.e. C code that does not rely on implementation-defined behaviour)?

Because LLVM IR already includes that implementation-defined behaviour.

Cameron