diff --git a/include/fast_float/ascii_number.h b/include/fast_float/ascii_number.h
index ba6b0ef..5327a79 100644
--- a/include/fast_float/ascii_number.h
+++ b/include/fast_float/ascii_number.h
@@ -71,7 +71,7 @@ uint64_t simd_read8_to_u64(const __m128i data) {
 FASTFLOAT_SIMD_DISABLE_WARNINGS
   const __m128i packed = _mm_packus_epi16(data, data);
 #ifdef FASTFLOAT_64BIT
-  return uint64_t(_mm_cvtsi128_si64x(packed));
+  return uint64_t(_mm_cvtsi128_si64(packed));
 #else
   uint64_t value;
   // Visual Studio + older versions of GCC don't support _mm_storeu_si64