diff --git a/js/src/assembler/wtf/Platform.h b/js/src/assembler/wtf/Platform.h
index 49c3388f2031..f929831ab6f0 100644
--- a/js/src/assembler/wtf/Platform.h
+++ b/js/src/assembler/wtf/Platform.h
@@ -165,16 +165,22 @@
     || defined(__POWERPC__) \
     || defined(_M_PPC)      \
     || defined(__PPC)
+#if !defined(__ppc64__) && !defined(__PPC64__)
 #define WTF_CPU_PPC 1
+#endif
+#if !defined(__LITTLE_ENDIAN__)
 #define WTF_CPU_BIG_ENDIAN 1
 #endif
+#endif
 
 /* WTF_CPU_PPC64 - PowerPC 64-bit */
 #if   defined(__ppc64__) \
     || defined(__PPC64__)
 #define WTF_CPU_PPC64 1
+#if !defined(__LITTLE_ENDIAN__)
 #define WTF_CPU_BIG_ENDIAN 1
 #endif
+#endif
 
 /* WTF_CPU_SH4 - SuperH SH-4 */
 #if defined(__SH4__)
diff --git a/js/src/configure.in b/js/src/configure.in
index 31a90497c4b6..4d6f933d11fd 100644
--- a/js/src/configure.in
+++ b/js/src/configure.in
@@ -934,7 +934,7 @@ case "$OS_TEST" in
     CPU_ARCH=x86
     ;;
 
-powerpc64 | ppc64)
+powerpc64 | ppc64 | powerpc64le | ppc64le)
     CPU_ARCH=ppc64
     ;;
 
diff --git a/js/src/jscpucfg.h b/js/src/jscpucfg.h
index 5008832c91c9..a7a00613bbe6 100644
--- a/js/src/jscpucfg.h
+++ b/js/src/jscpucfg.h
@@ -27,7 +27,7 @@
 # define IS_LITTLE_ENDIAN 1
 # undef  IS_BIG_ENDIAN
 
-#elif defined(__APPLE__)
+#elif defined(__APPLE__) || defined(__powerpc__) || defined(__ppc__)
 # if __LITTLE_ENDIAN__
 #  define IS_LITTLE_ENDIAN 1
 #  undef  IS_BIG_ENDIAN
@@ -89,8 +89,7 @@
 # endif
 
 #elif defined(__sparc) || defined(__sparc__) || \
-      defined(_POWER) || defined(__powerpc__) || \
-      defined(__ppc__) || defined(__hppa) || \
+      defined(_POWER) || defined(__hppa) || \
       defined(_MIPSEB) || defined(_BIG_ENDIAN)
 /* IA64 running HP-UX will have _BIG_ENDIAN defined.
  * IA64 running Linux will have endian.h and be handled above.