Add XOP aware ChaCha

ChaCha is about 50% faster using XOP for the rotates on AMD machines

chacha-simd.cpp

@@ -26,6 +26,10 @@
 # include <tmmintrin.h>
 #endif
 
+#ifdef __XOP__
+# include <ammintrin.h>
+#endif
+
 #if (CRYPTOPP_ARM_NEON_AVAILABLE)
 # include <arm_neon.h>
 #endif
@@ -47,24 +51,36 @@ ANONYMOUS_NAMESPACE_BEGIN
 template <unsigned int R>
 inline __m128i RotateLeft(const __m128i val)
 {
+#ifdef __XOP__
+	return _mm_roti_epi32(val, R);
+#else
 	return _mm_or_si128(_mm_slli_epi32(val, R), _mm_srli_epi32(val, 32-R));
+#endif
 }
 
-#ifdef __SSSE3__
+#if defined(__SSSE3__)
 template <>
 inline __m128i RotateLeft<8>(const __m128i val)
 {
+#ifdef __XOP__
+	return _mm_roti_epi32(val, R);
+#else
 	const __m128i mask = _mm_set_epi8(14,13,12,15, 10,9,8,11, 6,5,4,7, 2,1,0,3);
 	return _mm_shuffle_epi8(val, mask);
+#endif
 }
 
 template <>
 inline __m128i RotateLeft<16>(const __m128i val)
 {
+#ifdef __XOP__
+	return _mm_roti_epi32(val, R);
+#else
 	const __m128i mask = _mm_set_epi8(13,12,15,14, 9,8,11,10, 5,4,7,6, 1,0,3,2);
 	return _mm_shuffle_epi8(val, mask);
-}
 #endif
+}
+#endif  // SSE3
 
 #endif  // CRYPTOPP_SSE2_INTRIN_AVAILABLE || CRYPTOPP_SSE2_ASM_AVAILABLE