From: Richard Henderson <rth@twiddle.net>
To: Aurelien Jarno <aurelien@aurel32.net>, qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH RFC 7/9] tcg: replace ext/u_i32_i64 by a mov when not implemented
Date: Fri, 17 Jul 2015 07:30:52 +0100 [thread overview]
Message-ID: <55A8A11C.5030109@twiddle.net> (raw)
In-Reply-To: <1436958199-5181-8-git-send-email-aurelien@aurel32.net>
On 07/15/2015 12:03 PM, Aurelien Jarno wrote:
> When ext_i32_i64 and extu_i32_i64 ops are not implemented, this means
> that the register is already properly zero/sign extended, so we can
> simply replace it by a mov.
>
> In practice it means at least one of the two ops should always be
> implemented on 64-bit targets.
>
> Cc: Paolo Bonzini<pbonzini@redhat.com>
> Cc: Richard Henderson<rth@twiddle.net>
> Signed-off-by: Aurelien Jarno<aurelien@aurel32.net>
> ---
> tcg/tcg-op.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
If we're going to do this (and of course pick a solution for all of the other
backends), I think perhaps x86 should choose trunc + exts as the two that
should be implemented, leaving extu the one that can be folded away.
Something to experiment with...
r~
next prev parent reply other threads:[~2015-07-17 6:31 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-15 11:03 [Qemu-devel] [PATCH RFC 0/9] tcg: improve size changing ops Aurelien Jarno
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 1/9] tcg: rename trunc_shr_i32 into trunc_shr_i64_i32 Aurelien Jarno
2015-07-17 6:14 ` Richard Henderson
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 2/9] tcg: don't abuse TCG type in tcg_gen_trunc_shr_i64_i32 Aurelien Jarno
2015-07-17 6:14 ` Richard Henderson
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 3/9] tcg: implement real ext_i32_i64 and extu_i32_i64 ops Aurelien Jarno
2015-07-17 6:19 ` Richard Henderson
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 4/9] tcg/optimize: add optimizations for " Aurelien Jarno
2015-07-17 6:23 ` Richard Henderson
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 5/9] tcg/i386: implement " Aurelien Jarno
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 6/9] tcg/i386: document the way 32/64-bit conversions are handled Aurelien Jarno
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 7/9] tcg: replace ext/u_i32_i64 by a mov when not implemented Aurelien Jarno
2015-07-17 6:30 ` Richard Henderson [this message]
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 8/9] tcg/optimize: do not simplify size changing moves Aurelien Jarno
2015-07-17 6:38 ` Richard Henderson
2015-07-17 10:33 ` Aurelien Jarno
2015-07-18 7:24 ` Richard Henderson
2015-07-18 21:19 ` Aurelien Jarno
2015-07-15 11:03 ` [Qemu-devel] [PATCH RFC 9/9] tcg: update README about size changing ops Aurelien Jarno
2015-07-17 6:42 ` Richard Henderson
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