[PATCH 21/21] x86: Enable Link Time Optimization

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

LTO is opt-in per architecture because it usually needs some
fixes.

LTO needs THIN_ARCHIVES because standard binutils doesn't like mixing
assembler and LTO code with ld -r.

Enable LTO and THIN_ARCHIVES for x86

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 arch/x86/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8eed3f94bfc7..92650726f908 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -122,6 +122,8 @@ config X86
 	select HAVE_ARCH_VMAP_STACK		if X86_64
 	select HAVE_ARCH_WITHIN_STACK_FRAMES
 	select HAVE_CC_STACKPROTECTOR
+	select THIN_ARCHIVES			if LTO
+	select ARCH_SUPPORTS_LTO
 	select HAVE_CMPXCHG_DOUBLE
 	select HAVE_CMPXCHG_LOCAL
 	select HAVE_CONTEXT_TRACKING		if X86_64
-- 
2.13.6