From 7dd929dfdc5c52ce79b21bf557ff506e89acbf63 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Sat, 18 Jun 2016 23:05:02 +0100 Subject: [PATCH] configure: Make AVX2 test robust to non-ELF systems The AVX2 optimization test assumes that the object format is ELF and the system has the readelf utility. If this isn't true then configure might fail or emit a warning (since in a pipe "foo | bar >/dev/null 2>&1" does not redirect the stderr of foo, only of bar). Adjust the check so that if we don't have readelf or don't have an ELF object then we just don't enable the AVX2 optimization. Reported-by: Stefan Weil Signed-off-by: Peter Maydell Reviewed-by: Stefan Weil Message-id: 1466287502-18730-3-git-send-email-pmaydell@chiark.greenend.org.uk --- configure | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/configure b/configure index 395057bff8..8ead9754e9 100755 --- a/configure +++ b/configure @@ -1792,8 +1792,10 @@ int foo(void *a) __attribute__((ifunc("bar_ifunc"))); int main(int argc, char *argv[]) { return foo(argv[0]);} EOF if compile_object "" ; then - if readelf --syms $TMPO |grep "IFUNC.*foo" >/dev/null 2>&1; then - avx2_opt="yes" + if has readelf; then + if readelf --syms $TMPO 2>/dev/null |grep -q "IFUNC.*foo"; then + avx2_opt="yes" + fi fi fi