[PATCH 3.16.y-ckt 026/118] ARC: Override toplevel default -O2 with -O3

[Luis Henriques]

3.16.7-ckt16 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vineet Gupta <vgupta at synopsys.com>

commit 97709069214eb75312c14946803b9da4d3814203 upstream.

ARC kernels have historically been built with -O3, despite top level
Makefile defaulting to -O2. This was facilitated by implicitly ordering
of arch makefile include AFTER top level assigned -O2.

An upstream fix to top level a1c48bb160f ("Makefile: Fix unrecognized
cross-compiler command line options") changed the ordering, making ARC
-O3 defunct.

Fix that by NOT relying on any ordering whatsoever and use the proper
arch override facility now present in kbuild (ARCH_*FLAGS)

Depends-on: ("kbuild: Allow arch Makefiles to override {cpp,ld,c}flags")
Suggested-by: Michal Marek <mmarek at suse.cz>
Cc: Geert Uytterhoeven <geert at linux-m68k.org>
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arc/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 8c0b1aa56f7e..429279bc3028 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -44,7 +44,8 @@ endif
 
 ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
 # Generic build system uses -O2, we want -O3
-cflags-y  += -O3
+# Note: No need to add to cflags-y as that happens anyways
+ARCH_CFLAGS += -O3
 endif
 
 # small data is default for elf32 tool-chain. If not usable, disable it