From: Peter Meerwald <p.meerwald@xxxxxxxxxxxxxxxxxx> the check for NEON so far only checked if -mfpu=neon is understood by the compiler, however, this is not enough: (i) #include <arm_neon.h> should be checked (ii) -mfpu=neon must be passed before CFLAGS because eventually the per-library CFLAGS for NEON code in src/Makefile.am are passed to the compiler before the global CFLAGS in case the build environment passes CFLAGS to configure and we try to set conflicting CFLAGS option, the former take precedence; CFLAGS cannot be overridden this does not fix http://lists.freedesktop.org/archives/pulseaudio-discuss/2012-December/015570.html but at least makes the build fail in configure (and not while compiling stuff) and gives better diagnostics Signed-off-by: Peter Meerwald <p.meerwald at bct-electronic.com> --- configure.ac | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/configure.ac b/configure.ac index 8a02cb7..6857890 100644 --- a/configure.ac +++ b/configure.ac @@ -322,9 +322,9 @@ AC_ARG_ENABLE([neon-opt], AS_HELP_STRING([--enable-neon-opt], [Enable NEON optimisations on ARM CPUs that support it])) AS_IF([test "x$enable_neon_opt" != "xno"], - [save_CFLAGS="$CFLAGS"; CFLAGS="$CFLAGS -mfpu=neon" + [save_CFLAGS="$CFLAGS"; CFLAGS="-mfpu=neon $CFLAGS" AC_COMPILE_IFELSE( - AC_LANG_PROGRAM([], []), + AC_LANG_PROGRAM([[#include <arm_neon.h>]], []), [ HAVE_NEON=1 NEON_CFLAGS="-mfpu=neon" @@ -338,7 +338,7 @@ AS_IF([test "x$enable_neon_opt" != "xno"], [HAVE_NEON=0]) AS_IF([test "x$enable_neon_opt" = "xyes" && test "x$HAVE_NEON" = "x0"], - [AC_MSG_ERROR([*** Compiler does not support -mfpu=neon])]) + [AC_MSG_ERROR([*** Compiler does not support -mfpu=neon or CFLAGS override -mfpu])]) AC_SUBST(HAVE_NEON) AC_SUBST(NEON_CFLAGS) -- 1.7.9.5
