diff --git a/libc/src/__support/float_to_string.h b/libc/src/__support/float_to_string.h
--- a/libc/src/__support/float_to_string.h
+++ b/libc/src/__support/float_to_string.h
@@ -387,15 +387,9 @@
                                        const int32_t shift_amount) {
   constexpr size_t MANT_INT_SIZE = sizeof(MantissaInt) * 8;
   cpp::UInt<MID_INT_SIZE + MANT_INT_SIZE> val(large);
-  // TODO: Find a better way to force __uint128_t to be UInt<128>
-  cpp::UInt<MANT_INT_SIZE> wide_mant(0);
-  wide_mant[0] = static_cast<size_t>(mantissa & (uint64_t(-1)));
-  wide_mant[1] = static_cast<size_t>(mantissa >> 64);
-  val = (val * wide_mant) >> shift_amount;
-
+  val = (val * mantissa) >> shift_amount;
   return static_cast<uint32_t>(
       val.div_uint32_times_pow_2(1000000000, 0).value());
-  // return fast_uint_mod_1e9(val);
 }
 
 } // namespace internal