[llvm-dev] Testing "normal" cross-compilers versus GPU backends

[Robinson, Paul via llvm-dev]

> -----Original Message-----
> From: James Y Knight [mailto:jyknight at google.com]
> Sent: Friday, September 04, 2015 10:12 AM
> To: Mehdi Amini; Mehdi Amini via llvm-dev
> Cc: Robinson, Paul
> Subject: Re: [llvm-dev] Testing "normal" cross-compilers versus GPU
> backends
> 
> >>> The Hexagon precedent is interesting; Krzysztof said they set the
> default
> >>> triple, and didn't have to xfail all that much stuff.  Searching the
> tree,
> >>> I find exactly 7 individual tests marked XFAIL: hexagon, plus it
> disables
> >>> all of ExecutionEngine, and turns off the 'object-emission' feature.
> >>>
> >>> I'm curious if you would try setting the default triple to match your
> >>> target, and see what /kinds/ of tests fail.  The raw number is much
> less
> >>> interesting than in the categories.
> >>
> >> Failing tests attached, let me know which ones you’d like me to
> investigate.
> >
> > Tests:
> > <failing_tests>
> >
> > (note I forced enable the “native” feature on this run)
> 
> So, just looking at the first one in that list for an example, running:
> llc -mtriple amdgcn test/CodeGen/Generic/2002-04-14-
> UnexpectedUnsignedType.ll
> you get an error of:
> error: unsupported call to function bar in foo
> 
> ..because apparently AMDGPU simply doesn't support function calls. At all.
> 
> That is a rather unusual feature to be missing, and I'd imagine is causing
> a fair number of the other nominally-generic tests to fail too...

Hmm I'm told GPUs as a class typically don't support calls (everything has
to be inlined).

Perhaps the more appropriate direction here is to invent a "gpu" config flag
and mark some things XFAIL: gpu.
--paulr