diff --git a/libc/src/ctype/ctype_utils.h b/libc/src/__support/ctype_utils.h
rename from libc/src/ctype/ctype_utils.h
rename to libc/src/__support/ctype_utils.h
--- a/libc/src/ctype/ctype_utils.h
+++ b/libc/src/__support/ctype_utils.h
@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_CTYPE_CTYPE_UTILS_H
-#define LLVM_LIBC_SRC_CTYPE_CTYPE_UTILS_H
+#ifndef LLVM_LIBC_SRC_SUPPORT_CTYPE_UTILS_H
+#define LLVM_LIBC_SRC_SUPPORT_CTYPE_UTILS_H
 
 namespace __llvm_libc {
 namespace internal {
@@ -30,7 +30,11 @@
 
 static constexpr int isupper(unsigned ch) { return (ch - 'A') < 26; }
 
+static constexpr int isspace(unsigned ch) {
+  return ch == ' ' || (ch - '\t') < 5;
+}
+
 } // namespace internal
 } // namespace __llvm_libc
 
-#endif //  LLVM_LIBC_SRC_CTYPE_CTYPE_UTILS_H
+#endif //  LLVM_LIBC_SRC_SUPPORT_CTYPE_UTILS_H
diff --git a/libc/src/ctype/isalnum.cpp b/libc/src/ctype/isalnum.cpp
--- a/libc/src/ctype/isalnum.cpp
+++ b/libc/src/ctype/isalnum.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/isalnum.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/ctype/isalpha.cpp b/libc/src/ctype/isalpha.cpp
--- a/libc/src/ctype/isalpha.cpp
+++ b/libc/src/ctype/isalpha.cpp
@@ -9,7 +9,7 @@
 #include "src/ctype/isalpha.h"
 
 #include "src/__support/common.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 namespace __llvm_libc {
 
diff --git a/libc/src/ctype/isdigit.cpp b/libc/src/ctype/isdigit.cpp
--- a/libc/src/ctype/isdigit.cpp
+++ b/libc/src/ctype/isdigit.cpp
@@ -8,7 +8,7 @@
 
 #include "src/ctype/isdigit.h"
 #include "src/__support/common.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 namespace __llvm_libc {
 
diff --git a/libc/src/ctype/isgraph.cpp b/libc/src/ctype/isgraph.cpp
--- a/libc/src/ctype/isgraph.cpp
+++ b/libc/src/ctype/isgraph.cpp
@@ -9,7 +9,7 @@
 #include "src/ctype/isgraph.h"
 
 #include "src/__support/common.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 namespace __llvm_libc {
 
diff --git a/libc/src/ctype/islower.cpp b/libc/src/ctype/islower.cpp
--- a/libc/src/ctype/islower.cpp
+++ b/libc/src/ctype/islower.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/islower.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/ctype/ispunct.cpp b/libc/src/ctype/ispunct.cpp
--- a/libc/src/ctype/ispunct.cpp
+++ b/libc/src/ctype/ispunct.cpp
@@ -9,7 +9,7 @@
 #include "src/ctype/ispunct.h"
 
 #include "src/__support/common.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 namespace __llvm_libc {
 
diff --git a/libc/src/ctype/isspace.cpp b/libc/src/ctype/isspace.cpp
--- a/libc/src/ctype/isspace.cpp
+++ b/libc/src/ctype/isspace.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/isspace.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"
 
@@ -14,9 +15,6 @@
 
 // TODO: Currently restricted to default locale.
 // These should be extended using locale information.
-LLVM_LIBC_FUNCTION(int, isspace, (int c)) {
-  const unsigned ch = c;
-  return ch == ' ' || (ch - '\t') < 5;
-}
+LLVM_LIBC_FUNCTION(int, isspace, (int c)) { return internal::isspace(c); }
 
 } // namespace __llvm_libc
diff --git a/libc/src/ctype/isupper.cpp b/libc/src/ctype/isupper.cpp
--- a/libc/src/ctype/isupper.cpp
+++ b/libc/src/ctype/isupper.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/isupper.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/ctype/isxdigit.cpp b/libc/src/ctype/isxdigit.cpp
--- a/libc/src/ctype/isxdigit.cpp
+++ b/libc/src/ctype/isxdigit.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/isxdigit.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/ctype/tolower.cpp b/libc/src/ctype/tolower.cpp
--- a/libc/src/ctype/tolower.cpp
+++ b/libc/src/ctype/tolower.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/tolower.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/ctype/toupper.cpp b/libc/src/ctype/toupper.cpp
--- a/libc/src/ctype/toupper.cpp
+++ b/libc/src/ctype/toupper.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/ctype/toupper.h"
-#include "src/ctype/ctype_utils.h"
+#include "src/__support/ctype_utils.h"
 
 #include "src/__support/common.h"