From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Wed, 27 Sep 2017 17:34:23 -0500
Subject: objtool: Skip unreachable warnings for GCC 4.4 and older
Git-commit: da541b20021c781f8b65492eeaee824e729599eb
Patch-mainline: v4.14-rc3
References: bnc#1058115

The kbuild bot occasionally reports warnings like:

  drivers/scsi/pcmcia/aha152x_core.o: warning: objtool: seldo_run()+0x130: unreachable instruction

These warnings are always with GCC 4.4.  That version of GCC sometimes
places unreachable instructions after calls to noreturn functions.

The unreachable warnings aren't very important anyway.  Just ignore them
for old versions of GCC.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/bc89b807d965b98ec18a0bb94f96a594bd58f2f2.1506551639.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 scripts/Makefile.build |    2 ++
 1 file changed, 2 insertions(+)

--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -266,6 +266,8 @@ objtool_args += --no-fp
 endif
 ifdef CONFIG_GCOV_KERNEL
 objtool_args += --no-unreachable
+else
+objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 endif
 
 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory