[LLVMdev] Using non-system compiler to build llvm and llvm-gcc front end

Scott Ricketts sricketts at maxentric.com
Sat May 9 09:42:17 PDT 2009

>> $ make -j15
> do you really have 15 CPUs?  If not, this will most
> likely just slow things down.

I have 8 CPUs. I started with -j8 and turned the knob up a bit. It
seemed to run faster, so I stuck with j15. I guess there might be some
context switching when threads are blocking on memory or IO. I could
be imagining the speedups though because of some sort of placebo

>> cc1: /pkg/build/llvm/llvm/lib/Analysis/ScalarEvolution.cpp:511:
>> bool<unnamed>::SCEVComplexityCompare::operator()(const llvm::SCEV*,
>> const llvm::SCEV*) const: Assertion `0 && "Unknown SCEV kind!"'
>> failed.
>> ../../llvm-gcc/libdecnumber/decNumber.c:5591: internal compiler error: Aborted
>> This is all with llvm and llvm-gcc source from svn.
> Since the SCEV code is changing rapidly at the moment, it may be that you
> had the bad luck to update to a broken revision.

Release 2.5 was giving me problems (see older posts on this thread). I
will see if updating my current revision helps.

> This looks like a clear bug in your system tools: note how it complains
> that a certain section is referenced by itself, and that this is a problem
> because it is being discarded, d'oh!  There's not much we can do about this
> kind of thing.

OK, not quite sure what this means about my system tools. Is there
something I should be concerned about?

>> I have also tried installing with the llvm-gcc binary for RHEL4 (even
>> though I am running Centos 5). However, "make check" returned a bunch
>> of unexpected failures.
> If you want llvm from svn, then you should use llvm-gcc from svn too.

Yes, I assumed so. I was just getting frustrated with not being able
to build the svn llvm-gcc, so I tried the binary.

> Ciao,
> Duncan.

Thanks for your help.

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