[Polly][PATCH 7/8] [RTC] Build and print alias groups

[Tobias Grosser]

Hi Johannes,

I agree with the general approach here and the patch is very nicely
written.

One thing I wonder about is why you decided to build the alias checks 
already in ScopInfo? In your original patch they where build in the 
Codegeneration.cpp file, no? From my perspective this is mostly a code 
generation issue. So it seems building them right ahead is both 
conceptually a little unclean and it also means we always pay the cost 
of building alias checks even in cases where we do not need them.

(We do not exploit this at the moment, but I could see us stop to 
analyse/optimize a scop half-way through to avoid spending compile
time for cases where it is obvious that there is nothing to gain.)

It may very well be that there are good reasons to build those sets 
early so, but you just don't mention them at all. I would have expected 
those sets to already be build in IslAst.cpp to be able to pretty-print 
them, but I am surprised they are already built in ScopInfo.cpp. Also, 
even if they are build later, certain pieces of the code may very well 
stay in ScopInfo, but may be just called later on.

>   create mode 100644 test/Isl/CodeGen/MemAccess/codegen_simple_float.ll
>   create mode 100644 test/Isl/CodeGen/MemAccess/codegen_simple_md_float.ll
>   create mode 100644 test/Isl/CodeGen/MemAccess/simple___%for.cond---%for.end14.jscop
>   create mode 100644 test/Isl/CodeGen/MemAccess/simple___%for.cond---%for.end14.jscop.transformed

What are you testing here? This is not clear to me.

Cheers,
Tobias