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Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/li…
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…nux/kernel/git/tip/tip

Pull a x86/build change from Ingo Molnar.

This makes the default stack alignment on x86-64 be just 8, allowing for
improved code generation (it can avoid some unnecessary extra alignment
logic and use just pure push/pop sequences) and smaller stack frames.

We can't generally do SSE with 16-byte alignment issues in the kernel anyway.

* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86-64, gcc: Use -mpreferred-stack-boundary=3 if supported
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torvalds committed Jul 22, 2012
2 parents 2bd3488 + d9b0cde commit e2b34e3
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3 changes: 3 additions & 0 deletions arch/x86/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,9 @@ else
KBUILD_AFLAGS += -m64
KBUILD_CFLAGS += -m64

# Use -mpreferred-stack-boundary=3 if supported.
KBUILD_CFLAGS += $(call cc-option,-mno-sse -mpreferred-stack-boundary=3)

# FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
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