[Issue 13032] New: std.internal.math.gammfunction assumes 80-bit real

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13032

          Issue ID: 13032
           Summary: std.internal.math.gammfunction assumes 80-bit real
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: Phobos
          Assignee: nobody at puremagic.com
          Reporter: johannespfau at gmail.com

std.internal.math.gammfunction assumes that reals are in x86 Extended Precision
Format. This is only true for x86 and gammafunction is actually the only module
with failing tests on ARM.

A simple way to test for systems where real==double is to use the -mlong-double
flag with gdc:

----
#Install gdc via linux distribution or from gdcproject.org/downloads/
wget
http://gdcproject.org/downloads/binaries/x86_64-linux-gnu/native_2.065_gcc4.9.0_a8ad6a6678_20140615.tar.xz
tar xf native_2.065_gcc4.9.0_a8ad6a6678_20140615.tar.xz
wget
https://raw.githubusercontent.com/D-Programming-GDC/GDC/master/libphobos/src/std/internal/math/gammafunction.d
echo "void main(){}" > main.d
# With default precision, tests should pass on x86 systems
./x86_64-gdcproject-linux-gnu/bin/x86_64-unknown-linux-gnu-gdc gammafunction.d
main.d -funittest -g
./a.out
# With real==double precision, tests fail
./x86_64-gdcproject-linux-gnu/bin/x86_64-unknown-linux-gnu-gdc gammafunction.d
main.d -funittest  -g -mlong-double-64
./a.out
----

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