diff --git a/include/polarssl/bn_mul.h b/include/polarssl/bn_mul.h
index cffcd6b..1c2da13 100644
--- a/include/polarssl/bn_mul.h
+++ b/include/polarssl/bn_mul.h
@@ -548,7 +548,7 @@
 
 #if defined(__arm__)
 
-#if defined(__thumb__)
+#if defined(__thumb__) && !defined(__thumb2__)
 
 #define MULADDC_INIT                            \
     asm(                                        \
diff --git a/library/bignum.c b/library/bignum.c
index d9845da..1422d50 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -934,8 +934,16 @@
 
 /*
  * Helper for mpi multiplication
- */ 
-static void mpi_mul_hlp( size_t i, t_uint *s, t_uint *d, t_uint b )
+ */
+static
+#if defined(__APPLE__) && defined(__arm__)
+/*
+ * Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn)
+ * appears to need this to prevent bad ARM code generation at -O3.
+ */
+__attribute__ ((noinline))
+#endif
+void mpi_mul_hlp( size_t i, t_uint *s, t_uint *d, t_uint b )
 {
     t_uint c = 0, t = 0;