diff --git a/libc/src/__support/str_to_float.h b/libc/src/__support/str_to_float.h
--- a/libc/src/__support/str_to_float.h
+++ b/libc/src/__support/str_to_float.h
@@ -78,6 +78,8 @@
 }
 #endif
 
+#ifndef LIBC_SIZE
+
 // This Eisel-Lemire implementation is based on the algorithm described in the
 // paper Number Parsing at a Gigabyte per Second, Software: Practice and
 // Experience 51 (8), 2021 (https://arxiv.org/abs/2101.11408), as well as the
@@ -110,8 +112,9 @@
   uint32_t clz = leading_zeroes<BitsType>(mantissa);
   mantissa <<= clz;
 
-  uint32_t exp2 = static_cast<uint32_t>(exp10_to_exp2(exp10)) + BITS_IN_MANTISSA +
-                  fputil::FloatProperties<T>::EXPONENT_BIAS - clz;
+  uint32_t exp2 = static_cast<uint32_t>(exp10_to_exp2(exp10)) +
+                  BITS_IN_MANTISSA + fputil::FloatProperties<T>::EXPONENT_BIAS -
+                  clz;
 
   // Multiplication
   const uint64_t *power_of_ten =
@@ -149,8 +152,10 @@
   }
 
   // Shifting to 54 bits for doubles and 25 bits for floats
-  BitsType msb = static_cast<BitsType>(high64(final_approx) >> (BITS_IN_MANTISSA - 1));
-  BitsType final_mantissa = static_cast<BitsType>(high64(final_approx) >>
+  BitsType msb =
+      static_cast<BitsType>(high64(final_approx) >> (BITS_IN_MANTISSA - 1));
+  BitsType final_mantissa =
+      static_cast<BitsType>(high64(final_approx) >>
                             (msb + BITS_IN_MANTISSA -
                              (fputil::FloatProperties<T>::MANTISSA_WIDTH + 3)));
   exp2 -= static_cast<uint32_t>(1 ^ msb); // same as !msb
@@ -210,7 +215,8 @@
   uint32_t clz = leading_zeroes<BitsType>(mantissa);
   mantissa <<= clz;
 
-  uint32_t exp2 = static_cast<uint32_t>(exp10_to_exp2(exp10)) + BITS_IN_MANTISSA +
+  uint32_t exp2 = static_cast<uint32_t>(exp10_to_exp2(exp10)) +
+                  BITS_IN_MANTISSA +
                   fputil::FloatProperties<long double>::EXPONENT_BIAS - clz;
 
   // Multiplication
@@ -290,6 +296,8 @@
 }
 #endif
 
+#endif // LIBC_SIZE
+
 // The nth item in POWERS_OF_TWO represents the greatest power of two less than
 // 10^n. This tells us how much we can safely shift without overshooting.
 constexpr uint8_t POWERS_OF_TWO[19] = {
@@ -428,6 +436,7 @@
   *outputExp2 = exp2;
 }
 
+#ifndef LIBC_SIZE
 // This class is used for templating the constants for Clinger's Fast Path,
 // described as a method of approximation in
 // Clinger WD. How to Read Floating Point Numbers Accurately. SIGPLAN Not 1990
@@ -543,6 +552,7 @@
   *outputExp2 = result.get_unbiased_exponent();
   return true;
 }
+#endif // LIBC_SIZE
 
 // Takes a mantissa and base 10 exponent and converts it into its closest
 // floating point type T equivalient. First we try the Eisel-Lemire algorithm,
@@ -578,6 +588,7 @@
     return;
   }
 
+#ifndef LIBC_SIZE
   if (!truncated) {
     if (clinger_fast_path<T>(mantissa, exp10, outputMantissa, outputExp2)) {
       return;
@@ -600,6 +611,7 @@
       }
     }
   }
+#endif // LIBC_SIZE
 
   simple_decimal_conversion<T>(numStart, outputMantissa, outputExp2);
 
diff --git a/libc/test/src/__support/str_to_float_test.cpp b/libc/test/src/__support/str_to_float_test.cpp
--- a/libc/test/src/__support/str_to_float_test.cpp
+++ b/libc/test/src/__support/str_to_float_test.cpp
@@ -14,6 +14,7 @@
 
 class LlvmLibcStrToFloatTest : public __llvm_libc::testing::Test {
 public:
+#ifndef LIBC_SIZE
   template <class T>
   void clinger_fast_path_test(
       const typename __llvm_libc::fputil::FPBits<T>::UIntType inputMantissa,
@@ -62,7 +63,7 @@
     EXPECT_EQ(actual_output_mantissa, expectedOutputMantissa);
     EXPECT_EQ(actual_output_exp2, expectedOutputExp2);
   }
-
+#endif // LIBC_SIZE
   template <class T>
   void simple_decimal_conversion_test(
       const char *__restrict numStart,
@@ -120,6 +121,7 @@
   EXPECT_EQ(__llvm_libc::internal::leading_zeroes<uint32_t>(0xffffffff), 0u);
 }
 
+#ifndef LIBC_SIZE
 TEST_F(LlvmLibcStrToFloatTest, ClingerFastPathFloat64Simple) {
   clinger_fast_path_test<double>(123, 0, 0xEC00000000000, 1029);
   clinger_fast_path_test<double>(1234567890123456, 1, 0x5ee2a2eb5a5c0, 1076);
@@ -187,6 +189,7 @@
   ASSERT_FALSE(__llvm_libc::internal::eisel_lemire<float>(
       20040229, 0, &float_output_mantissa, &output_exp2));
 }
+#endif // LIBC_SIZE
 
 TEST_F(LlvmLibcStrToFloatTest, SimpleDecimalConversion64BasicWholeNumbers) {
   simple_decimal_conversion_test<double>("123456789012345678900",
@@ -262,6 +265,8 @@
   EXPECT_EQ(errno, 0);
 }
 
+#ifndef LIBC_SIZE
+
 #if defined(LONG_DOUBLE_IS_DOUBLE)
 TEST_F(LlvmLibcStrToFloatTest, EiselLemireFloat64AsLongDouble) {
   eisel_lemire_test<long double>(123, 0, 0x1EC00000000000, 1029);
@@ -344,3 +349,4 @@
       &quadOutputMantissa, &outputExp2));
 }
 #endif
+#endif // LIBC_SIZE