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Re: RTL definition

"Fran Baena" <> writes:

> 2008/3/10, Jim Wilson <>:
>> Fran Baena wrote:
>>  > RTL represents a low-level language, machine-independent. But I didn't
>>  > find any especification of such language represented. This is, I found
>>  > no document where the language represented were described or defined
>>  > in a grammar way.
>> RTL isn't a programming language, and hence has no grammar.  It is
>>  merely one of the internal representations that gcc uses for optimizing
>>  and generating code.  We do have gcc internals documentation that you
>>  have already been pointed at.
> i agree with you, RTL is not a programming language, is a language
> that is represented internally. But it could match a grammar
> definition. And this is my question, what is the process to define a
> RTL.

RTL is a set of data structures.  It's defined by rtl.def and rtl.h.
The closest thing to a grammar for RTL is rtl.def, which defines how
each of the fields are represented given the RTL code.

By the way, RTL is not really machine-independent.  The data
structures are machine independent.  But the contents are not.  You
can not, even in principle, take the RTL generated for one processor
and compile it on another processor.


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