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Re: fftw3: Patch for powerpc build failure

Hello Debian folks; I'm one of the FFTW authors, and we'd like to help you resolve this problem if we can. (Both my co-author and I run Debian on PowerPC G3 laptops.) I'll ping Matteo, who did most of the Altivec/SIMD work, when he returns. Unfortunately, I'm not sure whether either of us has access to an Altivec-supporting CPU with Debian; any chance of an account?

Note that FFTW has had a way of exposing gcc bugs, especially with SIMD (see http://www.fftw.org/faq/section2.html#compilerCrashes), and it sounds like you are seeing different results with different gcc versions...so that may be what is happening here. Ugh.

Michel Dänzer wrote:
-mabi=altivec to build tests/bench doesn't seem to make a difference
here (I do wonder whether all fftw3 dependants were or will be built
with it though...).

Can you tell us whether -mabi=altivec is really required for programs calling FFTW? I never did figure out exactly what this flag does on Linux. (It is not needed for 16-byte stack alignment, apparently, since I think that is guaranteed by the SVR4 ABI.)


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