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m68k: Optimize cc-option calls for cpuflags-y 

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>
Link: https://lore.kernel.org/r/20200526123810.301667-3-masahiroy@kernel.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Masahiro Yamada 2020-05-26 21:38:09 +09:00 committed by Geert Uytterhoeven
parent bd3ff3f1b6
commit 2367b02642
1 changed files with 24 additions and 21 deletions
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45
arch/m68k/Makefile
View File

@ -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)