From: David Hildenbrand <david@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Cc: Thomas Huth <thuth@redhat.com>, Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH v3 0/4] target/s390x: Improve carry computation
Date: Wed, 16 Dec 2020 15:44:31 +0100 [thread overview]
Message-ID: <a7c017b1-bfcf-9780-2cee-8096ec0fef23@redhat.com> (raw)
In-Reply-To: <20201214221356.68039-1-richard.henderson@linaro.org>
On 14.12.20 23:13, Richard Henderson wrote:
> While testing the float128_muladd changes for s390x host,
> emulating under x86_64 of course, I noticed that the code
> we generate for strings of ALCGR and SLBGR is pretty awful.
>
> I realized that we were missing a trick: the output cc is
> based only on the output (result and carry) and so we don't
> need to save the inputs. And once we do that, we can use
> the output carry as a direct input to the next insn.
>
LGTM, @Conny, can you pick these?
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-12-16 14:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-14 22:13 [PATCH v3 0/4] target/s390x: Improve carry computation Richard Henderson
2020-12-14 22:13 ` [PATCH v3 1/4] target/s390x: Improve cc computation for ADD LOGICAL Richard Henderson
2020-12-14 22:13 ` [PATCH v3 2/4] target/s390x: Improve ADD LOGICAL WITH CARRY Richard Henderson
2020-12-14 22:13 ` [PATCH v3 3/4] target/s390x: Improve cc computation for SUBTRACT LOGICAL Richard Henderson
2020-12-14 22:13 ` [PATCH v3 4/4] target/s390x: Improve SUB LOGICAL WITH BORROW Richard Henderson
2020-12-16 14:44 ` David Hildenbrand [this message]
2020-12-16 17:09 ` [PATCH v3 0/4] target/s390x: Improve carry computation Cornelia Huck
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