[LLVMdev] testing instruction selection

[reed kotler]

On 02/22/2013 07:51 AM, Sean Silva wrote:
> Do you have any suggestions about how to address this?
>
> -- Sean Silva
Ideally we would define an ascii representation for DAGS.

It should be possible to start the compiler from the DAGS as opposed to 
LLVM assembler bitcode.

It should also be possible to compile a C file or LLVM assembler bitcode 
file and save off the DAGS ascii file.

Believe it or not, they had this over 30 years ago with the PQCC 
(Production Quality Compiler Compiler ) project at Carnegie Mellon.
Intermetrics where I worked had a commercial version of this and later 
Tartan Laboratories.
http://en.wikipedia.org/wiki/PQCC

Any phase of the compiler had an ascii representation that could be 
parsed into binary stuctures and then submitted to that phase and 
optionally propagated to later phases. You could also save off the state 
of any phase in ascii too.

So you could write test cases for optimizations and code generation that 
were reproducible and such.

In those days they used various YAML ancient precursors like LG and IDL.

We used to jokingly call the PQCC project PQTG (Product Quality Thesis 
Generator).

Reed


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