From 7e95ba87878dc053355ef3829aa20a24060cd4f6 Mon Sep 17 00:00:00 2001
From: Wayne Davison <wayne@opencoder.net>
Date: Sun, 21 Jun 2020 08:05:19 -0700
Subject: [PATCH] Add -fno-slp-vectorize to clang++.

---
 configure.ac | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/configure.ac b/configure.ac
index cc6769ab..d8bc1013 100644
--- a/configure.ac
+++ b/configure.ac
@@ -249,6 +249,9 @@ if test x"$SIMD" != x""; then
     SIMD='$(SIMD_'"$SIMD)"
     # We only use c++ for its target attribute dispatching, disable unneeded bulky features
     CXXFLAGS="$CXXFLAGS -fno-exceptions -fno-rtti"
+    case "$CXX" in
+    *clang*) CXXFLAGS="$CXXFLAGS -fno-slp-vectorize" ;; # avoid a performance hit
+    esac
 else
     AC_MSG_RESULT(no)
 fi
-- 
2.47.2