Commit 4fb8320a authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Paolo Bonzini
Browse files

avx2 configure: Use primitives in test 



Use the avx2 primitives during the test, thus making sure that the
compiler and assembler could actually use avx2.

This also detects the failure case on gcc 4.8.x with -save-temps
and avoids the need for the gcc version check in cutils.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1465557378-24105-3-git-send-email-dgilbert@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent fc6e1de9

configure

+12 −5
Original line number Diff line number Diff line
@@ -1779,13 +1779,20 @@ fi 
# avx2 optimization requirement check



cat > $TMPC << EOF

static void bar(void) {}

#pragma GCC push_options

#pragma GCC target("avx2")

#include <cpuid.h>

#include <immintrin.h>



static int bar(void *a) {

    return _mm256_movemask_epi8(_mm256_cmpeq_epi8(*(__m256i *)a, (__m256i){0}));

}

static void *bar_ifunc(void) {return (void*) bar;}

void foo(void) __attribute__((ifunc("bar_ifunc")));

int main(void) { foo(); return 0; }

int foo(void *a) __attribute__((ifunc("bar_ifunc")));

int main(int argc, char *argv[]) { return foo(argv[0]);}

EOF

if compile_prog "-mavx2" "" ; then

    if readelf --syms $TMPE |grep "IFUNC.*foo" >/dev/null 2>&1; then

if compile_object "" ; then

    if readelf --syms $TMPO |grep "IFUNC.*foo" >/dev/null 2>&1; then

        avx2_opt="yes"

    fi

fi

util/cutils.c

+1 −7
Original line number Diff line number Diff line
@@ -256,13 +256,7 @@ static size_t buffer_find_nonzero_offset_inner(const void *buf, size_t len) 
    return i * sizeof(VECTYPE);

}



/*

 * GCC before version 4.9 has a bug which will cause the target

 * attribute work incorrectly and failed to compile in some case,

 * restrict the gcc version to 4.9+ to prevent the failure.

 */



#if defined CONFIG_AVX2_OPT && QEMU_GNUC_PREREQ(4, 9)

#if defined CONFIG_AVX2_OPT

#pragma GCC push_options

#pragma GCC target("avx2")

#include <cpuid.h>