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References: <20190301115413.27153-1-david@redhat.com>
	<20190301115413.27153-14-david@redhat.com>
From: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <546b95fb-09a7-d406-40d0-f33a55deecb4@linaro.org>
Date: Fri, 1 Mar 2019 08:26:20 -0800
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Subject: Re: [Qemu-devel] [PATCH v2 13/32] s390x/tcg: Implement VECTOR LOAD
 MULTIPLE
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To: David Hildenbrand <david@redhat.com>, qemu-devel@nongnu.org
Cc: qemu-s390x@nongnu.org, Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>, Richard Henderson <rth@twiddle.net>

On 3/1/19 3:53 AM, David Hildenbrand wrote:
> +    /*
> +     * Check for possible access exceptions by trying to load the last
> +     * element. The first element will be checked first next.
> +     */
> +    t = tcg_temp_new_i64();
> +    gen_addi_and_wrap_i64(s, t, o->addr1, (v3 - v1) * 16 + 8);
> +    tcg_gen_qemu_ld_i64(t, t, get_mem_index(s), MO_TEQ);

qemu_ld expands to enough code that it is a shame to discard this value and
reload it during this loop.  Perhaps load this to t2...

> +
> +    for (;; v1++) {
> +        tcg_gen_qemu_ld_i64(t, o->addr1, get_mem_index(s), MO_TEQ);
> +        write_vec_element_i64(t, v1, 0, ES_64);

Move v1 == v3 break here...

> +        gen_addi_and_wrap_i64(s, o->addr1, o->addr1, 8);
> +        tcg_gen_qemu_ld_i64(t, o->addr1, get_mem_index(s), MO_TEQ);
> +        write_vec_element_i64(t, v1, 1, ES_64);
> +        if (v1 == v3) {
> +            break;
> +        }
> +        gen_addi_and_wrap_i64(s, o->addr1, o->addr1, 8);
> +    }

... and store t2 into v3 element 1 after the loop.


r~