From c2f7718b63018038e3cbd366d472c241958ef72d Mon Sep 17 00:00:00 2001
From: Matthieu Schaller <schaller@strw.leidenuniv.nl>
Date: Fri, 18 Oct 2019 22:29:35 +0200
Subject: [PATCH] Only set the AVX512 flags with GCC when compiling with a
version that supports the flag.
---
configure.ac | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/configure.ac b/configure.ac
index 47baa529d2..7ccf1d023c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -71,6 +71,13 @@ AC_USE_SYSTEM_EXTENSIONS
AX_COMPILER_VENDOR
AX_COMPILER_VERSION
+# Check whether we have a recent enough GCC
+if test "$ax_cv_c_compiler_vendor" = "gnu"; then
+ AX_COMPARE_VERSION([$ax_cv_c_compiler_version], [ge], [8.1.0],
+ [gcc_handles_avx512="yes"],
+ [gcc_handles_avx512="no"])
+fi
+
# Restrict support.
AC_C_RESTRICT
@@ -462,14 +469,18 @@ if test "$enable_opt" = "yes" ; then
;;
esac
elif test "$ax_cv_c_compiler_vendor" = "gnu"; then
- case "$ax_gcc_arch" in
- *skylake-avx512*)
- GRAVITY_CFLAGS="$GRAVITY_CFLAGS -mprefer-vector-width=512"
- ;;
- *)
- AC_MSG_WARN([No additional flags needed for gravity on this platform])
- ;;
- esac
+ if test "$gcc_handles_avx512" = "yes"; then
+ case "$ax_gcc_arch" in
+ *skylake-avx512*)
+ [GRAVITY_CFLAGS="$GRAVITY_CFLAGS -mprefer-vector-width=512"],
+ ;;
+ *)
+ AC_MSG_WARN([No additional flags needed for gravity on this platform])
+ ;;
+ esac
+ else
+ AC_MSG_WARN([No additional flags needed for gravity on this platform])
+ fi
else
AC_MSG_WARN([Do not know what best gravity vectorization flags to choose for this compiler])
fi
--
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