From: Ralf Baechle <ralf@linux-mips.org>
To: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org, "stable # v4 . 4+" <stable@vger.kernel.org>
Subject: Re: [PATCH] MIPS: Remove compact branch policy Kconfig entries
Date: Tue, 13 Sep 2016 14:43:14 +0200 [thread overview]
Message-ID: <20160913124314.GA20655@linux-mips.org> (raw)
In-Reply-To: <20160912095806.4411-1-paul.burton@imgtec.com>
On Mon, Sep 12, 2016 at 10:58:06AM +0100, Paul Burton wrote:
> Fixing this by hiding the Kconfig entry behind another seems to be more
> hassle than it's worth, as MIPSr6 & compact branches have been around
> for a while now and if policy does need to be set for debug it can be
> done easily enough with KCFLAGS. Therefore remove the compact branch
> policy Kconfig entries & their handling in the Makefile.
I've applied your patch - and given where we are wrt. to R6 I think this
simply and bulletproof solution is certainly the right thing.
But, have you considered probing for the option and only using it where
it actually is available with something like:
cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_NEVER) += $(call cc-option,-mcompact-branches=never)
cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_OPTIMAL) += $(call cc-option,-mcompact-branches=optimal)
cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_ALWAYS) += $(call cc-option,-mcompact-branches=always)
?
I'm also wondering how much we gain from -mcompact-branches?
Ralf
next prev parent reply other threads:[~2016-09-13 12:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-12 9:58 [PATCH] MIPS: Remove compact branch policy Kconfig entries Paul Burton
2016-09-12 9:58 ` Paul Burton
2016-09-13 12:43 ` Ralf Baechle [this message]
2016-09-13 17:27 ` Paul Burton
2016-09-13 17:27 ` Paul Burton
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