Bug#916504: pulseaudio FTBFS on Alpha; return of the volume-test failure

Felipe Sateler fsateler at debian.org
Wed Jan 16 01:00:40 GMT 2019

Control: forwarded -1
Control: retitle -1 pulseaudio: uses -ffinite-math but might deal with


Sorry for the delay.

On Sat, Dec 15, 2018 at 3:24 AM Michael Cree <mcree at orcon.net.nz> wrote:

> Source: pulseaudio
> Version: 12.2-2
> Severity: important
> Justification: fails to build from source but built in the past.
> User: debian-alpha at lists.debian.org
> Usertags: alpha
> Tags: patch
> Pulseaudio FTBFS on alpha due to the volume-test test failing due to
> a floating-point exception which in turn is due to an infinity in
> floating-point calculations when volume-test is compiled with finite
> math options.
> This is bug #798248 reappearing but in a subtlely different guise.
> There the non-finite math was protected against by checking that the
> arguments are finite before performing floating point calculations,
> but it now seems that gcc takes the specification of finite math,
> being "[a]llow optimizations for floating-point arithmetic that
> assume that arguments and results are not NaNs or +-Infs" so
> pedantically true, that it is fair game to optimise away any calls
> to isfinite() because the argument must be finite: it was said so
> on the command line!
> Whatever, examination of the object code shows that the calls to
> isfinite() are eliminated thus the floating-point arithmetic is no
> longer protected.

I think if infinities might happen, then using -ffinite-math is wrong.

I have forwarded the issue upstream. I have disabled -ffast-math in the
meantime, since I think correctness is more important than speed.

> Fortunately we can work out whether the arguments to the offending
> arithmetic are finite by other means and I attach a patch doing
> just that.  With this patch pulseaudio builds to completion on
> Alpha.

This is insufficient as there is a call to isnan() in the core lib.

Felipe Sateler
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