From: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> I just noted that -mtune is used, which is only supported on recent GCCs; by reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in the appropriate cases. However -mcpu is deprecated, so use -mtune when possible.
This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use of -march, since that could trigger gcc using SSE on its own. But no attention was used about using -mcpu vs. -mtune. And btw, the old 2.6.4 code (for instance) was: cflags-$(CONFIG_MPENTIUMII) += $(call check_gcc,-march=pentium2,-march=i686) cflags-$(CONFIG_MPENTIUMIII) += $(call check_gcc,-march=pentium3,-march=i686) cflags-$(CONFIG_MPENTIUMM) += $(call check_gcc,-march=pentium3,-march=i686) cflags-$(CONFIG_MPENTIUM4) += $(call check_gcc,-march=pentium4,-march=i686) Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> --- arch/i386/Makefile.cpu | 18 +++++++++++++----- 1 files changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/i386/Makefile.cpu b/arch/i386/Makefile.cpu --- a/arch/i386/Makefile.cpu +++ b/arch/i386/Makefile.cpu @@ -1,6 +1,14 @@ # CPU tuning section - shared with UML. # Must change only cflags-y (or [yn]), not CFLAGS! That makes a difference for UML. +#-mtune exists since gcc 3.4, and some -mcpu flavors didn't exist in gcc 2.95. +HAS_MTUNE := $(call cc-option-yn, -mtune=i386) +ifeq ($(HAS_MTUNE),y) +tune = $(call cc-option,-mtune=$(1),) +else +tune = $(call cc-option,-mcpu=$(1),) +endif + align := $(cc-option-align) cflags-$(CONFIG_M386) += -march=i386 cflags-$(CONFIG_M486) += -march=i486 @@ -8,17 +16,17 @@ cflags-$(CONFIG_M586) += -march=i586 cflags-$(CONFIG_M586TSC) += -march=i586 cflags-$(CONFIG_M586MMX) += $(call cc-option,-march=pentium-mmx,-march=i586) cflags-$(CONFIG_M686) += -march=i686 -cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call cc-option,-mtune=pentium2) -cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call cc-option,-mtune=pentium3) -cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call cc-option,-mtune=pentium3) -cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call cc-option,-mtune=pentium4) +cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call tune,pentium2) +cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call tune,pentium3) +cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call tune,pentium3) +cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call tune,pentium4) cflags-$(CONFIG_MK6) += -march=k6 # Please note, that patches that add -march=athlon-xp and friends are pointless. # They make zero difference whatsosever to performance at this time. cflags-$(CONFIG_MK7) += $(call cc-option,-march=athlon,-march=i686 $(align)-functions=4) cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,$(call cc-option,-march=athlon,-march=i686 $(align)-functions=4)) cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0 -cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call cc-option,-mtune=pentium3) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0 +cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0 cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586) cflags-$(CONFIG_MWINCHIP2) += $(call cc-option,-march=winchip2,-march=i586) cflags-$(CONFIG_MWINCHIP3D) += $(call cc-option,-march=winchip2,-march=i586) ------------------------------------------------------- This SF.Net email is sponsored by the JBoss Inc. Get Certified Today * Register for a JBoss Training Course Free Certification Exam for All Training Attendees Through End of 2005 Visit http://www.jboss.com/services/certification for more information _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
