http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54463
--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-09-05 10:21:53 UTC --- (In reply to comment #1) > This bug report should be closed. Combining > -fexternal-blas and -fdefault-real-8 would > add needless complexity to the compiler. I think a patch like mine in comment 2 should be sufficient and it not that complex. > The correct solution is to write proper Fortran > code. To be even more specific, don't use > -fdefault-real-8. It was a really, really, > bad idea and was only supplied to give > backwards compatibility with g77. Well, many compilers have such a flag and there are several programs which rely on the presence of such a flag. It might not be the most sensible to write programs that way, but it is common enough that a compiler should support it. [Comment to my patch:] (In reply to comment #3) > What about -freal-4-real-10 -freal-4-real-16 -freal-4-real-8 > -freal-8-real-10 -freal-8-real-16 and -freal-8-real-4? Ugh, those flags are ugly! (Actually, I think you approved that patch, which I regard as worse than -fdefault-real-8.) the -freal-*-real-* flags completely messes up everything. However, since everything is handled in primary.c/decl.c, the internal kind numbers should be fine. (There are bits in trans-types.c, but they only error out when a given kind doesn't exist.) Of course, I assume that one doesn't mess around with -fdefault-real-8 or -freal-4-real-10 when compiling BLAS. If one does this, one gets what one deserves.