diff --git a/src/sincos.h b/src/sincos.h
index 6b36814d1f5dbec3d03f06dbeab6502d036ef88b..340c8d7b841f6f172a84e3e3c6e88c0b2e6e6618 100644
--- a/src/sincos.h
+++ b/src/sincos.h
@@ -41,11 +41,11 @@
  * @param cos (return) The cosine of x.
  */
 __attribute__((always_inline)) INLINE static void sincos(const double x,
-                                                         double *sin,
-                                                         double *cos) {
+                                                         double *restrict s,
+                                                         double *restrict c) {
 
-  *sin = sin(x);
-  *cos = cos(x);
+  *s = sin(x);
+  *c = cos(x);
 }
 
 #endif
@@ -63,11 +63,11 @@ __attribute__((always_inline)) INLINE static void sincos(const double x,
  * @param cos (return) The cosine of x.
  */
 __attribute__((always_inline)) INLINE static void sincosf(const float x,
-                                                          float *sin,
-                                                          float *cos) {
+                                                          float *restrict s,
+                                                          float *restrict c) {
 
-  *sin = sinf(x);
-  *cos = cosf(x);
+  *s = sinf(x);
+  *c = cosf(x);
 }
 
 #endif