[Bug 1879092] Re: gfortran can't use vectorized functions.

[Launchpad Bug Tracker]

This bug was fixed in the package glibc - 2.31-0ubuntu9.1

---------------
glibc (2.31-0ubuntu9.1) focal; urgency=medium

  [ Michael Hudson-Doyle ]
  * Mark tst-getpw as XFAIL on arm64. (LP: #1869364)

  [ Matthias Klose ]
  * Copy the fully conditionalized x86 variant for math-vector-fortran.h
    to /usr/include/finclude. On all architectures. (LP: #1879092)

  [ Balint Reczey ]
  * debian/gbp.conf: Add initial configuration
  * debian/control.in/main: Add Vcs-* pointing to Ubuntu packaging repository
  * debian/debhelper.in/libc.preinst: Fix setting LDCONFIG_NOTRIGGER
    (LP: #1889190)
  * Fall back to calling nanosleep syscall when __clock_nanosleep returns
    EINVAL due to CLOCK_REALTIME not being supported (LP: #1871129)
  * debian/testsuite-xfail-debian.mk: XFAIL tst-getpw on armhf, too
    (LP: #1869364)
  * XFAIL stdlib/tst-getrandom (LP: #1891403)

  [ Dimitri John Ledkov ]
  * debian/patches/powerpc: Cherrypick upstream patches to support POWER10
    optimized library loading. LP: #1887989

 -- Balint Reczey <rbalint at ubuntu.com>  Mon, 17 Aug 2020 22:02:52 +0200

** Changed in: glibc (Ubuntu Focal)
       Status: Fix Committed => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to gcc-10 in Ubuntu.
https://bugs.launchpad.net/bugs/1879092

Title:
  gfortran can't use vectorized functions.

Status in gcc-10 package in Ubuntu:
  New
Status in glibc package in Ubuntu:
  Fix Released
Status in gcc-10 source package in Focal:
  New
Status in glibc source package in Focal:
  Fix Released
Status in gcc-10 source package in Groovy:
  New
Status in glibc source package in Groovy:
  Fix Released

Bug description:
  [Impact]

  After ubuntu-glibc maintainers changed "math-vector-fortran.h" install
  directory (LP#1861353), gfortran can no longer use it.

  [Test Case]

  This the old (good) behavior Ubuntu 19.10 gcc-9.2.1 glibc 2.30
  $ gfortran -O3 -mavx2 vect_test.f90 -o test.x
  $ nm ./test.x | grep sin
      U _ZGVdN4v_sin@@GLIBC_2.22
      U _ZGVdN8v_sinf@@GLIBC_2.22

  After that change : Ubuntu 20.04 gcc-9.3.0 glibc 2.31
  $ gfortran -O3 -mavx2 vect_test.f90 -o test.x
  $ nm ./test.x | grep sin
      U sin@@GLIBC_2.2.5
      U sinf@@GLIBC_2.2.5

  $ cat vect_test.f90
  program test_vect
    implicit none
    integer, parameter :: n = 64*1024**2
    integer :: i
    integer(8) :: t1, t2, t0
    real(8) :: tic
    !
    real, allocatable :: a32(:), b32(:)
    real(8), allocatable :: a64(:), b64(:)
    !
    allocate( a32(n), a64(n))
    allocate( b32(n), b64(n))
    !
    call random_number(a32 )
    call random_number(a64 )
    !
    call system_clock(t0, tic)
    !
    do i = 1, n
      b32(i) = sin(a32(i))
    end do
    !
    call system_clock(t1)
    print*, (t1-t0)/tic
    !
    do i = 1, n
      b64(i) = sin(a64(i))
    end do
    !
    call system_clock(t2)
    print*, (t2-t1)/tic
    !
  end program test_vect

  Verbose:

  Ubuntu 19.10
  $ gfortran -O3 -mavx2 -v vect_test.f90 -o test.x
  ...
  /usr/lib/gcc/x86_64-linux-gnu/9/f951 vect_test.f90 -quiet -dumpbase vect_test.f90 -mavx2 -mtune=generic -march=x86-64 -auxbase vect_test -O3 -version -fintrinsic-modules-path /usr/lib/gcc/x86_64-linux-gnu/9/finclude -fpre-include=/usr/include/finclude/math-vector-fortran.h -o /tmp/cc2E2K8s.s
  ...

  Ubuntu 20.04
  $ gfortran -O3 -mavx2 -v vect_test.f90 -o test.x
  ...
  /usr/lib/gcc/x86_64-linux-gnu/9/f951 vect_test.f90 -quiet -dumpbase vect_test.f90 -mavx2 -mtune=generic -march=x86-64 -auxbase vect_test -O3 -version -fintrinsic-modules-path /usr/lib/gcc/x86_64-linux-gnu/9/finclude -o /tmp/cc4swJwz.s
  ...

  [Other Info]

  As you can see gfortran is not preincluding "math-vector-fortran.h" file on Ubuntu 20.04.
  A workaround is to copy "math-vector-fortran.h" to /usr/include/finclude (which is empty!).

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/gcc-10/+bug/1879092/+subscriptions