neon/add: implement vaddd_s64 and vaddd_u64

arm/neon/add.h

@@ -33,6 +33,34 @@ HEDLEY_DIAGNOSTIC_PUSH
 SIMDE_DISABLE_UNWANTED_DIAGNOSTICS
 SIMDE_BEGIN_DECLS_
 
+SIMDE_FUNCTION_ATTRIBUTES
+int64_t
+simde_vaddd_s64(int64_t a, int64_t b) {
+  #if defined(SIMDE_ARM_NEON_A64V8_NATIVE)
+    return vaddd_s64(a, b);
+  #else
+    return a + b;
+  #endif
+}
+#if defined(SIMDE_ARM_NEON_A64V8_ENABLE_NATIVE_ALIASES)
+  #undef vaddd_s64
+  #define vaddd_s64(a, b) simde_vaddd_s64((a), (b))
+#endif
+
+SIMDE_FUNCTION_ATTRIBUTES
+uint64_t
+simde_vaddd_u64(uint64_t a, uint64_t b) {
+  #if defined(SIMDE_ARM_NEON_A64V8_NATIVE)
+    return vaddd_u64(a, b);
+  #else
+    return a + b;
+  #endif
+}
+#if defined(SIMDE_ARM_NEON_A64V8_ENABLE_NATIVE_ALIASES)
+  #undef vaddd_u64
+  #define vaddd_u64(a, b) simde_vaddd_u64((a), (b))
+#endif
+
 SIMDE_FUNCTION_ATTRIBUTES
 simde_float32x2_t
 simde_vadd_f32(simde_float32x2_t a, simde_float32x2_t b) {