From 094259452467acbf6e1214f3a65a17c56fbe60fc Mon Sep 17 00:00:00 2001
From: Le Philousophe <lephilousophe@users.noreply.github.com>
Date: Sun, 1 Sep 2024 18:51:11 +0200
Subject: [PATCH] CONFIGURE: Enable back SIMD for clang compiler depending on
 its version

---
 configure | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 1b65aca283f..4f56a2d074b 100755
--- a/configure
+++ b/configure
@@ -2282,6 +2282,9 @@ if test "$have_gcc" = yes; then
 		cxx_version="`echo "${cxx_version}" | sed -e 's/"\([^ ]*\) .*/\1/'`"
 		cxx_version="clang $cxx_version, ok"
 
+		_clang_major=`gcc_get_define __clang_major__`
+		_clang_minor=`gcc_get_define __clang_minor__`
+
 		append_var CXXFLAGS "-Wshadow"
 	else
 		cxx_version="GCC $cxx_version, ok"
@@ -7133,7 +7136,35 @@ case $_host_cpu in
 		;;
 esac
 
-if test "$have_gcc" = yes; then
+if test "$have_clang" = yes; then
+	# Clang has variable support to target gating of intrinsics
+	case $_host_cpu in
+	i[3-6]86)
+		# SSE2 and AVX2 has been target gated since LLVM 5.0
+		if (test $_clang_major -lt 5) || (test $_clang_major -eq 5 && test $_clang_minor -lt 0); then
+			_ext_sse2=no
+			_ext_avx2=no
+		fi
+		;;
+	arm*)
+		# NEON has been target gated since LLVM 19.1
+		if (test $_clang_major -lt 19) || (test $_clang_major -eq 19 && test $_clang_minor -lt 1); then
+			# But several platforms enables it globally...
+			if ! echo "$CXXFLAGS" | grep -q -e -mfpu=neon; then
+				_ext_neon=no
+			fi
+		fi
+		;;
+	x86_64 | amd64)
+		# AVX2 has been target gated since LLVM 5.0
+		# x86_64 always supports SSE2, no need of gating
+		if (test $_clang_major -lt 5) || (test $_clang_major -eq 5 && test $_clang_minor -lt 0); then
+			_ext_avx2=no
+		fi
+		;;
+	# aarch64 always supports NEON, no need of gating
+	esac
+elif test "$have_gcc" = yes; then
 	# Need 4.9 for pragma target
 	if (test $_cxx_major -lt 4) || (test $_cxx_major -eq 4 && test $_cxx_minor -lt 9); then
 		_ext_sse2=no