intern/cycles/util/math_fast.h

@@ -59,8 +59,11 @@ ccl_device_inline int fast_rint(float x)
 {
   /* used by sin/cos/tan range reduction. */
 #ifdef __KERNEL_SSE41__
-  /* Single `roundps` instruction on SSE4.1+ (for gcc/clang at least). */
-  return float_to_int(rintf(x));
+  /* Single `roundps` instruction on SSE4.1+ for gcc/clang but not MSVC 19.35:
+   * float_to_int(rintf(x)); so we use the equivalent intrinsics. */
+  __m128 vec = _mm_set_ss(x);
+  vec = _mm_round_ss(vec, vec, (_MM_FROUND_TO_NEAREST_INT | _MM_FROUND_NO_EXC));
+  return _mm_cvtss_si32(vec);
 #else
   /* emulate rounding by adding/subtracting 0.5. */
   return float_to_int(x + copysignf(0.5f, x));