Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 29 Jun 2020 19:47:17 +0200 | Subject | Re: [PATCH 3/4] m68k: optimize cc-option calls for cpuflags-y |
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On Tue, May 26, 2020 at 2:38 PM Masahiro Yamada <masahiroy@kernel.org> 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>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> i.e. will queue in the m68k for-v5.9 branch.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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