diff --git a/examples/intrinsics/knl.h b/examples/intrinsics/knl.h
index f23623c2..82c003ae 100644
--- a/examples/intrinsics/knl.h
+++ b/examples/intrinsics/knl.h
@@ -2615,7 +2615,7 @@ static FORCEINLINE __vec16_f __sqrt_varying_float(__vec16_f v) {
 
 static FORCEINLINE __vec16_f __rcp_varying_float(__vec16_f v) {
 #ifdef ISPC_FAST_MATH
-  return _mm512_rcp23_ps(v); // Approximation with 23 bits of accuracy.
+  return _mm512_rcp28_ps(v); // Approximation with 28 bits of accuracy.
 #else
   return _mm512_recip_ps(v);
 #endif
@@ -2634,7 +2634,7 @@ static FORCEINLINE double __rcp_uniform_double(double v)
 
 static FORCEINLINE __vec16_f __rsqrt_varying_float(__vec16_f v) {
 #ifdef ISPC_FAST_MATH
-  return _mm512_rsqrt23_ps(v); // Approximation with 0.775ULP accuracy
+  return _mm512_rsqrt28_ps(v); // Approximation with 28 bits of accuracy
 #else 
   return _mm512_invsqrt_ps(v);
 #endif