diff --git a/include/fast_float/float_common.h b/include/fast_float/float_common.h
index 3769972..1b2594e 100644
--- a/include/fast_float/float_common.h
+++ b/include/fast_float/float_common.h
@@ -325,147 +325,22 @@ struct is_supported_char_type
                              > {
 };
 
-template <typename UC>
-inline FASTFLOAT_CONSTEXPR14 bool
-fastfloat_strncasecmp3(UC const *actual_mixedcase,
-                       UC const *expected_lowercase) {
-  uint64_t mask{0};
-  FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 1) { mask = 0x2020202020202020; }
-  else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 2) {
-    mask = 0x0020002000200020;
-  }
-  else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 4) {
-    mask = 0x0000002000000020;
-  }
-  else {
-    return false;
-  }
-
-  uint64_t val1{0}, val2{0};
-  if (cpp20_and_in_constexpr()) {
-    for (size_t i = 0; i < 3; i++) {
-      if ((actual_mixedcase[i] | 32) != expected_lowercase[i]) {
-        return false;
-      }
-    }
-    return true;
-  } else {
-    FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 1 || sizeof(UC) == 2) {
-      ::memcpy(&val1, actual_mixedcase, 3 * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase, 3 * sizeof(UC));
-      val1 |= mask;
-      val2 |= mask;
-      return val1 == val2;
-    }
-    else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 4) {
-      ::memcpy(&val1, actual_mixedcase, 2 * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase, 2 * sizeof(UC));
-      val1 |= mask;
-      if (val1 != val2) {
-        return false;
-      }
-      return (actual_mixedcase[2] | 32) == (expected_lowercase[2]);
-    }
-    else {
-      return false;
-    }
-  }
-}
-
-template <typename UC>
-inline FASTFLOAT_CONSTEXPR14 bool
-fastfloat_strncasecmp5(UC const *actual_mixedcase,
-                       UC const *expected_lowercase) {
-  uint64_t mask{0};
-  uint64_t val1{0}, val2{0};
-  if (cpp20_and_in_constexpr()) {
-    for (size_t i = 0; i < 5; i++) {
-      if ((actual_mixedcase[i] | 32) != expected_lowercase[i]) {
-        return false;
-      }
-    }
-    return true;
-  } else {
-    FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 1) {
-      mask = 0x2020202020202020;
-      ::memcpy(&val1, actual_mixedcase, 5 * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase, 5 * sizeof(UC));
-      val1 |= mask;
-      val2 |= mask;
-      return val1 == val2;
-    }
-    else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 2) {
-      mask = 0x0020002000200020;
-      ::memcpy(&val1, actual_mixedcase, 4 * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase, 4 * sizeof(UC));
-      val1 |= mask;
-      if (val1 != val2) {
-        return false;
-      }
-      return (actual_mixedcase[4] | 32) == (expected_lowercase[4]);
-    }
-    else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 4) {
-      mask = 0x0000002000000020;
-      ::memcpy(&val1, actual_mixedcase, 2 * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase, 2 * sizeof(UC));
-      val1 |= mask;
-      if (val1 != val2) {
-        return false;
-      }
-      ::memcpy(&val1, actual_mixedcase + 2, 2 * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase + 2, 2 * sizeof(UC));
-      val1 |= mask;
-      if (val1 != val2) {
-        return false;
-      }
-      return (actual_mixedcase[4] | 32) == (expected_lowercase[4]);
-    }
-    else {
-      return false;
-    }
-  }
-}
-
-// Compares two ASCII strings in a case insensitive manner.
+// Compares two ASCII strings in a case insensitive manner. The expected
+// string is lowercase ASCII, so OR-ing 0x20 into each actual character maps
+// 'A'..'Z' onto 'a'..'z' and leaves everything else mismatched. The lengths
+// used are tiny constants (3 and 5), so the compiler unrolls this loop; keep
+// it small so that the (rarely executed) inf/nan path does not bloat the hot
+// parser it is inlined into.
 template <typename UC>
 inline FASTFLOAT_CONSTEXPR14 bool
 fastfloat_strncasecmp(UC const *actual_mixedcase, UC const *expected_lowercase,
                       size_t length) {
-  uint64_t mask{0};
-  FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 1) { mask = 0x2020202020202020; }
-  else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 2) {
-    mask = 0x0020002000200020;
-  }
-  else FASTFLOAT_IF_CONSTEXPR17(sizeof(UC) == 4) {
-    mask = 0x0000002000000020;
-  }
-  else {
-    return false;
-  }
-
-  if (cpp20_and_in_constexpr()) {
-    for (size_t i = 0; i < length; i++) {
-      if ((actual_mixedcase[i] | 32) != expected_lowercase[i]) {
-        return false;
-      }
+  for (size_t i = 0; i < length; ++i) {
+    if ((actual_mixedcase[i] | 32) != expected_lowercase[i]) {
+      return false;
     }
-    return true;
-  } else {
-    uint64_t val1{0}, val2{0};
-    size_t sz{8 / (sizeof(UC))};
-    for (size_t i = 0; i < length; i += sz) {
-      val1 = val2 = 0;
-      sz = sz < (length - i) ? sz : length - i;
-      ::memcpy(&val1, actual_mixedcase + i, sz * sizeof(UC));
-      ::memcpy(&val2, expected_lowercase + i, sz * sizeof(UC));
-      val1 |= mask;
-      val2 |= mask;
-      if (val1 != val2) {
-        return false;
-      }
-    }
-    return true;
   }
+  return true;
 }
 
 #ifndef FLT_EVAL_METHOD
diff --git a/include/fast_float/parse_number.h b/include/fast_float/parse_number.h
index 14d077b..febfdc7 100644
--- a/include/fast_float/parse_number.h
+++ b/include/fast_float/parse_number.h
@@ -35,7 +35,7 @@ from_chars_result_t<UC>
     ++first;
   }
   if (last - first >= 3) {
-    if (fastfloat_strncasecmp3(first, str_const_nan<UC>())) {
+    if (fastfloat_strncasecmp(first, str_const_nan<UC>(), 3)) {
       answer.ptr = (first += 3);
       value = minusSign ? -std::numeric_limits<T>::quiet_NaN()
                         : std::numeric_limits<T>::quiet_NaN();
@@ -54,9 +54,9 @@ from_chars_result_t<UC>
       }
       return answer;
     }
-    if (fastfloat_strncasecmp3(first, str_const_inf<UC>())) {
+    if (fastfloat_strncasecmp(first, str_const_inf<UC>(), 3)) {
       if ((last - first >= 8) &&
-          fastfloat_strncasecmp5(first + 3, str_const_inf<UC>() + 3)) {
+          fastfloat_strncasecmp(first + 3, str_const_inf<UC>() + 3, 5)) {
         answer.ptr = first + 8;
       } else {
         answer.ptr = first + 3;