LLVM inquiry

Hi

This is Gaurav Khanna, from MacResearch.org - a community for
scientists that use the Mac and related hardware for research. One
service we perform for the community is supply g77 & gfortran
compilers for Mac OS X (which are not supplied by Apple).

We are interested in the progress made by LLVM and have some quick
questions. We'd appreciate any comments you can make.

1) What is the status of fortran/llvm-gfortran in the context of LLVM?
Are there any plans to support fortran?
2) Are you planning to use the GCC-based front-end in the long-term
or is that just temporary?
3) Are there any performance numbers available comparing with standard
GCC?

Thanks very much.
Gaurav

"Use The Archives, Luke!"

Seriously, search the llvmdev archives for recent llvm fortran results. :slight_smile:

-scooter

Hi,

1) What is the status of fortran/llvm-gfortran in the context of LLVM?
Are there any plans to support fortran?

gfortran works pretty well. You'll have to build it from the llvm-gcc
source yourself though (you need to add fortran to the --enable-languages
list). There are some known bugs, which are most of the llvm bugs with
numbers from 2441 to 2450. I don't know if it builds on the mac.

2) Are you planning to use the GCC-based front-end in the long-term
or is that just temporary?

No one has volunteered to write a clang-like front-end for Fortran yet,
so it's just llvm-gfortran for the moment.

3) Are there any performance numbers available comparing with standard
GCC?

Yes, see http://lists.cs.uiuc.edu/pipermail/llvmdev/2008-June/015441.html
The conclusion is that llvm-gfortran is on the whole a bit slower than
mainline.
There are some Fortran programs in the llvm testsuite but currently they
are compiled using g2c followed by llvm-gcc (C front-end) IIRC, rather
than using llvm-gfortran. It would be great if someone could tweak the
testsuite to use llvm-gfortran if it is available.

I hope this helps.

Best wishes,

Duncan.