From: Richard Henderson <rth@twiddle.net>
To: Aurelien Jarno <aurelien@aurel32.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 7/7] tcg-i386: Perform tail call to qemu_ret_ld*_mmu
Date: Thu, 29 Aug 2013 10:43:33 -0700 [thread overview]
Message-ID: <521F8845.3020102@twiddle.net> (raw)
In-Reply-To: <20130829170622.GP5908@ohm.aurel32.net>
On 08/29/2013 10:06 AM, Aurelien Jarno wrote:
> On Tue, Aug 27, 2013 at 02:46:31PM -0700, Richard Henderson wrote:
>> This does require the fast path always load to the function return
>> value register, but apparently the loaded value usually needs to be
>> spilled back to its memory slot anyway so the change in register
>> does not really change much.
>
> My suggestion was to only do that for the store, not for the load.
Ah, ok. Fair enough.
Shall I include the tail-call for store only if it saves code space,
due any possible concern for call-return stack?
I'm thinking here of PPC, which is 100% space neutral on this,
exchanging one B for one MTLR in order to implement the tail call.
r~
prev parent reply other threads:[~2013-08-29 17:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-27 21:46 [Qemu-devel] [PATCH 0/7] Further tcg ldst improvements Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 1/7] exec: Reorganize the GETRA/GETPC macros Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 2/7] tcg-i386: Don't perform GETPC adjustment in TCG code Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 3/7] exec: Rename USUFFIX to LSUFFIX Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 4/7] target: Include softmmu_exec.h where forgotten Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 5/7] exec: Split softmmu_defs.h Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 6/7] tcg: Introduce zero and sign-extended versions of load helpers Richard Henderson
2013-08-27 21:46 ` [Qemu-devel] [PATCH 7/7] tcg-i386: Perform tail call to qemu_ret_ld*_mmu Richard Henderson
2013-08-28 16:34 ` Richard Henderson
2013-08-29 15:31 ` Paolo Bonzini
2013-08-29 16:08 ` Richard Henderson
2013-08-29 16:36 ` Paolo Bonzini
2013-08-29 17:06 ` Aurelien Jarno
2013-08-29 17:43 ` Richard Henderson [this message]
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