[git commit master] workaround GCC PR32219

[Bernhard Reutner-Fischer]

commit: http://git.uclibc.org/uClibc/commit/?id=2e53dd645d5348f207cec7f8595969dc566c5a55
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/master

we ended up calling 0
Fixes bug #1033

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop at gmail.com>
---
 libc/misc/internals/__uClibc_main.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/libc/misc/internals/__uClibc_main.c b/libc/misc/internals/__uClibc_main.c
index f9e1244..4ee4443 100644
--- a/libc/misc/internals/__uClibc_main.c
+++ b/libc/misc/internals/__uClibc_main.c
@@ -105,6 +105,17 @@ _pthread_cleanup_pop_restore(struct _pthread_cleanup_buffer *__buffer,
 
 #endif /* !SHARED */
 
+/* Defeat compiler optimization which assumes function addresses are never NULL */
+static __always_inline int not_null_ptr(const void *p)
+{
+	const void *q;
+	asm (""
+		: "=r" (q) /* output */
+		: "0" (p) /* input */
+	);
+	return q != 0;
+}
+
 /*
  * Prototypes.
  */
@@ -254,7 +265,7 @@ void __uClibc_init(void)
 
 #ifdef __UCLIBC_HAS_LOCALE__
     /* Initialize the global locale structure. */
-    if (likely(_locale_init!=NULL))
+    if (likely(not_null_ptr(_locale_init)))
 	_locale_init();
 #endif
 
@@ -264,7 +275,7 @@ void __uClibc_init(void)
      * Thus we get a nice size savings because the stdio functions
      * won't be pulled into the final static binary unless used.
      */
-    if (likely(_stdio_init != NULL))
+    if (likely(not_null_ptr(_stdio_init)))
 	_stdio_init();
 
 }
-- 
1.6.3.3