Pulseaudio fails to build on the Alpha architecture due to a failure
in the volume-test of the test suite. I had reported this to the
Debian bug tracker [1] but the maintainer has asked that I forward the
patch to this mail list. The failure in volume-test occurs because it
is compiled with -ffast-math which implies -ffinite-math-only of which
the gcc manual states that it optimizes for floating-point arithmetic
with the assumption that arguments and results are not NaNs or
+/-infinity, and futher notes that it may result in incorrect output.
On the Alpha platform that is somewhat an understatement as the use of
non-finite floating-point arithmetic with -ffinite-math-only results in
a floating-point exception and the termination of the program.
The volume-test converts volumes into decibels (so a zero volume
becomes a negative infinity) and proceeds to add two volumes (in
decibels), thus does arithmetic with non-finite floating point numbers
despite being compiled with -ffast-math!
I attach a patch that protects against the arithmetic with non-finite
numbers for your consideration. With that patch the test-suite passes
on Alpha.
Cheers
Michael.
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=798248
Index: pulseaudio-6.0/src/tests/volume-test.c
===================================================================
--- pulseaudio-6.0.orig/src/tests/volume-test.c
+++ pulseaudio-6.0/src/tests/volume-test.c
@@ -114,7 +114,10 @@ START_TEST (volume_test) {
double q, qq;
p = pa_sw_volume_multiply(v, w);
- qq = db + db2;
+ if (isfinite(db) && isfinite(db2))
+ qq = db + db2;
+ else
+ qq = -INFINITY;
p2 = pa_sw_volume_from_dB(qq);
q = l*t;
p1 = pa_sw_volume_from_linear(q);
