Your message dated Tue, 16 May 2017 13:42:11 +0200
with message-id <958308f2-982b-03d1-5f7b-7af5e8183...@gmail.com>
and subject line [fftw] Neon now works on arm64
has caused the Debian Bug report #734675,
regarding fftw3: Fix configury for neon support on arm64 (armv8)
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
734675: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=734675
Debian Bug Tracking System
Contact ow...@bugs.debian.org with problems
--- Begin Message ---
Source: fftw3
Version: 3.3.3-7
Severity: normal
Tags: patch
User: debian-...@lists.debian.org
Usertag: arm64
In version 3.3.3-6 arm64 was added to the --enable-neon arch list. This
is correct in principle but doesn't work because both the enabling
compiler option and the compiler define have changed between the 32-bit
armv7 (for which this code was written) and armv8 (the 64-bit arch,
called 'arm64' in debian and 'aarch64' by ARM and GNU triplets).
neon is always enabled on armv8/arm64 unless explictly disabled so the
-mfpu=neon option is not understood by the arm64/aarch64 compiler. Also
__ARM_NEON__ is not defined by the compiler. So this needs changes in
configure.ac and simd-neon.h
However, applying this doesn't in fact get a working build as it exposes
a compiler ICE in the gcc4.8 we are currently using in unstable. But
that should get fixed soon.
Note that full support for arm64 will include enabling double-precision,
as that is available in armv8 neon, and writing code to support it.
Also note that armv8 has fused multiply-accumulate by default, which
apparently needs to be recorded for this package. I failed to understand
exactly what was going on with that so have not changed anything in this
patch, not least because doing so prduced another failure to build, as
have_fma and --enable-neon are deemed incompatible.
-- System Information:
Debian Release: 7.3
APT prefers stable
APT policy: (990, 'stable')
Architecture: i386 (i686)
Kernel: Linux 3.2.0-kvm-i386-20110111 (SMP w/1 CPU core)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
diff -Nru fftw3-3.3.3/debian/changelog fftw3-3.3.3/debian/changelog
--- fftw3-3.3.3/debian/changelog 2013-10-27 13:32:57.000000000 +0000
+++ fftw3-3.3.3/debian/changelog 2014-01-07 18:04:54.000000000 +0000
@@ -1,3 +1,9 @@
+fftw3 (3.3.3-7arm641) unstable; urgency=low
+
+ * Correct neon arm64 support in configurey
+
+ -- <enevill@apm2> Tue, 07 Jan 2014 18:03:45 +0000
+
fftw3 (3.3.3-7) unstable; urgency=low
* restrict architectures of long dependency of libfftw3-3 (Closes: #710890)
diff -Nru fftw3-3.3.3/debian/patches/arm64-neon-config.patch fftw3-3.3.3/debian/patches/arm64-neon-config.patch
--- fftw3-3.3.3/debian/patches/arm64-neon-config.patch 1970-01-01 00:00:00.000000000 +0000
+++ fftw3-3.3.3/debian/patches/arm64-neon-config.patch 2014-01-07 18:43:56.000000000 +0000
@@ -0,0 +1,27 @@
+Index: fftw3-3.3.3/configure.ac
+===================================================================
+--- fftw3-3.3.3.orig/configure.ac 2012-11-25 12:33:44.000000000 +0000
++++ fftw3-3.3.3/configure.ac 2014-01-07 18:25:34.890000000 +0000
+@@ -273,7 +273,8 @@
+ [AC_MSG_ERROR([Need a version of gcc with -maltivec])])])])
+ fi
+
+- if test "$have_neon" = "yes" -a "x$NEON_CFLAGS" = x; then
++ # armhf (no flag needed on arm64)
++ if test "$host_cpu" = "arm" -a "$have_neon" = "yes" -a "x$NEON_CFLAGS" = x; then
+ AX_CHECK_COMPILER_FLAGS(-mfpu=neon, [NEON_CFLAGS="-mfpu=neon"],
+ [AC_MSG_ERROR([Need a version of gcc with -mfpu=neon])])
+ fi
+Index: fftw3-3.3.3/simd-support/simd-neon.h
+===================================================================
+--- fftw3-3.3.3.orig/simd-support/simd-neon.h 2012-11-25 12:33:44.000000000 +0000
++++ fftw3-3.3.3/simd-support/simd-neon.h 2014-01-07 18:43:48.500000000 +0000
+@@ -29,7 +29,7 @@
+ #define SIMD_VSTRIDE_OKA(x) ((x) == 2)
+ #define SIMD_STRIDE_OKPAIR SIMD_STRIDE_OK
+
+-#if defined(__GNUC__) && !defined(__ARM_NEON__)
++#if defined(__GNUC__) && !defined(__ARM_NEON__) && !defined (__aarch64__)
+ #error "compiling simd-neon.h requires -mfpu=neon or equivalent"
+ #endif
+
diff -Nru fftw3-3.3.3/debian/patches/series fftw3-3.3.3/debian/patches/series
--- fftw3-3.3.3/debian/patches/series 2013-10-27 13:32:57.000000000 +0000
+++ fftw3-3.3.3/debian/patches/series 2014-01-07 17:38:41.000000000 +0000
@@ -5,3 +5,4 @@
texinfo5-compat.patch
wisdom-manpage.patch
fix-fftw-wisdom-to-conf.patch
+arm64-neon-config.patch
--- End Message ---
--- Begin Message ---
Version: 3.3.6p2
Since versions 3.3.5 the changes to the configuration are provided by
upstream. The 3.3.6 version in Debian now also invokes it. Thanks go
to N30dG for his initial suggestions and also for having confirmed
the Debian package to work on his arm64 infrastructure.
--- End Message ---
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