Messages in this thread | | | Subject | Re: [PATCH 3/4] m68k: optimize cc-option calls for cpuflags-y | From | Greg Ungerer <> | Date | Wed, 27 May 2020 22:55:47 +1000 |
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On 26/5/20 10:38 pm, Masahiro Yamada wrote: > arch/m68k/Makefile computes lots of unneeded cc-option calls. > > For example, if CONFIG_M5441x is not defined, there is not point in > evaluating the following compiler flag. > > cpuflags-$(CONFIG_M5441x) := $(call cc-option,-mcpu=54455,-mcfv4e) > > The result is set to cpuflags-, then thrown away. > > The right hand side of ':=' is immediately expanded. Hence, all of the > 16 calls for cc-option are evaluated. This is expensive since cc-option > invokes the compiler. This occurs even if you are not attempting to > build anything, like 'make ARCH=m68k help'. > > Use '=' to expand the value _lazily_. The evaluation for cc-option is > delayed until $(cpuflags-y) is expanded. So, the cc-option test happens > just once at most. > > This commit mimics tune-y of arch/arm/Makefile. > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Regards Greg
> --- > > arch/m68k/Makefile | 45 ++++++++++++++++++++++++--------------------- > 1 file changed, 24 insertions(+), 21 deletions(-) > > diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile > index 88d4d8bbecd6..ae6e29da3a3e 100644 > --- a/arch/m68k/Makefile > +++ b/arch/m68k/Makefile > @@ -32,30 +32,33 @@ endif > # compiler cpu type flag. > # > ifndef CONFIG_M68040 > -cpuflags-$(CONFIG_M68060) := -m68060 > +cpuflags-$(CONFIG_M68060) = -m68060 > endif > ifndef CONFIG_M68060 > -cpuflags-$(CONFIG_M68040) := -m68040 > +cpuflags-$(CONFIG_M68040) = -m68040 > endif > -cpuflags-$(CONFIG_M68030) := > -cpuflags-$(CONFIG_M68020) := > -cpuflags-$(CONFIG_M68000) := -m68000 > -cpuflags-$(CONFIG_M5441x) := $(call cc-option,-mcpu=54455,-mcfv4e) > -cpuflags-$(CONFIG_M54xx) := $(call cc-option,-mcpu=5475,-m5200) > -cpuflags-$(CONFIG_M5407) := $(call cc-option,-mcpu=5407,-m5200) > -cpuflags-$(CONFIG_M532x) := $(call cc-option,-mcpu=532x,-m5307) > -cpuflags-$(CONFIG_M537x) := $(call cc-option,-mcpu=537x,-m5307) > -cpuflags-$(CONFIG_M5307) := $(call cc-option,-mcpu=5307,-m5200) > -cpuflags-$(CONFIG_M528x) := $(call cc-option,-mcpu=528x,-m5307) > -cpuflags-$(CONFIG_M5275) := $(call cc-option,-mcpu=5275,-m5307) > -cpuflags-$(CONFIG_M5272) := $(call cc-option,-mcpu=5272,-m5307) > -cpuflags-$(CONFIG_M5271) := $(call cc-option,-mcpu=5271,-m5307) > -cpuflags-$(CONFIG_M523x) := $(call cc-option,-mcpu=523x,-m5307) > -cpuflags-$(CONFIG_M525x) := $(call cc-option,-mcpu=5253,-m5200) > -cpuflags-$(CONFIG_M5249) := $(call cc-option,-mcpu=5249,-m5200) > -cpuflags-$(CONFIG_M520x) := $(call cc-option,-mcpu=5208,-m5200) > -cpuflags-$(CONFIG_M5206e) := $(call cc-option,-mcpu=5206e,-m5200) > -cpuflags-$(CONFIG_M5206) := $(call cc-option,-mcpu=5206,-m5200) > +cpuflags-$(CONFIG_M68030) = > +cpuflags-$(CONFIG_M68020) = > +cpuflags-$(CONFIG_M68000) = -m68000 > +cpuflags-$(CONFIG_M5441x) = $(call cc-option,-mcpu=54455,-mcfv4e) > +cpuflags-$(CONFIG_M54xx) = $(call cc-option,-mcpu=5475,-m5200) > +cpuflags-$(CONFIG_M5407) = $(call cc-option,-mcpu=5407,-m5200) > +cpuflags-$(CONFIG_M532x) = $(call cc-option,-mcpu=532x,-m5307) > +cpuflags-$(CONFIG_M537x) = $(call cc-option,-mcpu=537x,-m5307) > +cpuflags-$(CONFIG_M5307) = $(call cc-option,-mcpu=5307,-m5200) > +cpuflags-$(CONFIG_M528x) = $(call cc-option,-mcpu=528x,-m5307) > +cpuflags-$(CONFIG_M5275) = $(call cc-option,-mcpu=5275,-m5307) > +cpuflags-$(CONFIG_M5272) = $(call cc-option,-mcpu=5272,-m5307) > +cpuflags-$(CONFIG_M5271) = $(call cc-option,-mcpu=5271,-m5307) > +cpuflags-$(CONFIG_M523x) = $(call cc-option,-mcpu=523x,-m5307) > +cpuflags-$(CONFIG_M525x) = $(call cc-option,-mcpu=5253,-m5200) > +cpuflags-$(CONFIG_M5249) = $(call cc-option,-mcpu=5249,-m5200) > +cpuflags-$(CONFIG_M520x) = $(call cc-option,-mcpu=5208,-m5200) > +cpuflags-$(CONFIG_M5206e) = $(call cc-option,-mcpu=5206e,-m5200) > +cpuflags-$(CONFIG_M5206) = $(call cc-option,-mcpu=5206,-m5200) > + > +# Evaluate tune cc-option calls now > +cpuflags-y := $(cpuflags-y) > > KBUILD_AFLAGS += $(cpuflags-y) > KBUILD_CFLAGS += $(cpuflags-y) >
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