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From: Matthias Kaehlcke <mka@chromium.org>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	grundler@chromium.org, Greg Hackmann <ghackmann@google.com>,
	Michael Davidson <md@google.com>,
	Matthias Kaehlcke <mka@chromium.org>
Subject: [PATCH] x86/kbuild: Use cc-option to enable -falign-{jumps/loops}
Date: Thu, 13 Apr 2017 10:26:09 -0700
Message-ID: <20170413172609.118122-1-mka@chromium.org> (raw)

clang currently does not support these optimizations, only enable them
when they are available.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---
 arch/x86/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index a94a4d10f2df..73604e18447a 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -88,10 +88,10 @@ else
         KBUILD_CFLAGS += -m64
 
         # Align jump targets to 1 byte, not the default 16 bytes:
-        KBUILD_CFLAGS += -falign-jumps=1
+        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
 
         # Pack loops tightly as well:
-        KBUILD_CFLAGS += -falign-loops=1
+        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
 
         # Don't autogenerate traditional x87 instructions
         KBUILD_CFLAGS += $(call cc-option,-mno-80387)
-- 
2.12.2.715.g7642488e1d-goog

             reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-13 17:26 Matthias Kaehlcke [this message]
2017-04-18  7:25 ` [tip:x86/build] " tip-bot for Matthias Kaehlcke

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