diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index e10f5c2..74ff481 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,3 +1,7 @@
+2015-11-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>
+
+	* libc/machine/arm/strlen.c: Refactor nested #if.
+
 2015-11-12  Anton Kolesov  <Anton.Kolesov@synopsys.com>
 
 	* configure.host: Add ARC support.
diff --git a/newlib/libc/machine/arm/strlen.c b/newlib/libc/machine/arm/strlen.c
index 7e59e75..ac5d47d 100644
--- a/newlib/libc/machine/arm/strlen.c
+++ b/newlib/libc/machine/arm/strlen.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008 ARM Ltd
+ * Copyright (c) 2008-2015 ARM Ltd
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,32 +31,12 @@
 #include <string.h>
 #include <limits.h>
 
-#if defined (__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED) || \
-  (defined (__thumb__) && !defined (__thumb2__))
-
-# if !defined (PREFER_SIZE_OVER_SPEED) && !defined (__OPTIMIZE_SIZE__)
-/* Thumb1 only variant.
-   If speed is preferred, the strlen() function in ../../string/strlen.c
-   will be used.
-
-   Leave this field blank.  So the strlen() is not defined, and this will
-   automatically pull in the default C definition of strlen() from
-   ../../string/strlen.c.  No need to include this file explicitely.
-   The lib_a-strlen.o will not be generated, so it won't replace the default
-   lib_a-strlen.o which is generated by ../../string/strlen.c.  See the
-   commands in configure.in and Makefile.am for more details.
-
-   However, if we need to rewrite this function to be more efficient,
-   we can add the corresponding assembly code into this field and change
-   the commands in configure.in and Makefile.am to allow the corresponding
-   lib_a-strlen.o to be generated.
-*/
-# else
+#if defined __OPTIMIZE_SIZE__ || defined PREFER_SIZE_OVER_SPEED
+#if defined __thumb__ && !defined __thumb2__
 size_t
 strlen (const char* str)
 {
   int scratch;
-#if defined (__thumb__) && !defined (__thumb2__)
   size_t len;
   asm ("mov	%0, #0\n"
        "1:\n\t"
@@ -66,7 +46,13 @@ strlen (const char* str)
        "bne	1b"
        : "=&r" (len), "=&r" (scratch) : "r" (str) : "memory", "cc");
   return len - 1;
+}
+
 #else
+size_t
+strlen (const char* str)
+{
+  int scratch;
   const char* end;
   asm ("1:\n\t"
        "ldrb	%1, [%0], #1\n\t"
@@ -74,13 +60,17 @@ strlen (const char* str)
        "bne	1b"
        : "=&r" (end), "=&r" (scratch) : "0" (str) : "memory", "cc");
   return end - str - 1;
-#endif
 }
 #endif
-#else
 
-#if !(defined(_ISA_ARM_7) || defined(__ARM_ARCH_6T2__))
+#else /* defined __OPTIMIZE_SIZE__ || defined PREFER_SIZE_OVER_SPEED */
+#if defined __thumb__ && ! defined __thumb2__
+  /* Implemented in ../../string/strlen.c.  */
+
+#elif defined _ISA_ARM_7 || defined __ARM_ARCH_6T2__
+  /* Implemented in strlen-armv7.S.  */
 
+#else
 size_t __attribute__((naked))
 strlen (const char* str)
 {
-- 
1.9.1