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: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1465557378-24105-3-git-send-email-dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2016-06-10 12:16:18 +01:00 committed by Paolo Bonzini
parent fc6e1de9d8
commit 4fb8320a2e
2 changed files with 13 additions and 12 deletions

17
configure vendored
View file

@ -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

View file

@ -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>