From: Richard Sandiford <richard.sandiford@arm.com>
To: Tamar Christina <Tamar.Christina@arm.com>
Cc: Richard Biener <rguenther@suse.de>, nd <nd@arm.com>,
"gcc-patches\@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH 1/4]middle-end Vect: Add support for dot-product where the sign for the multiplicant changes.
Date: Tue, 22 Jun 2021 12:16:47 +0100 [thread overview]
Message-ID: <mpt7dimcfog.fsf@arm.com> (raw)
In-Reply-To: <mptim26cgmj.fsf@arm.com> (Richard Sandiford's message of "Tue, 22 Jun 2021 11:56:20 +0100")
Richard Sandiford <richard.sandiford@arm.com> writes:
>> @@ -992,21 +1029,27 @@ vect_recog_dot_prod_pattern (vec_info *vinfo,
>> /* FORNOW. Can continue analyzing the def-use chain when this stmt in a phi
>> inside the loop (in case we are analyzing an outer-loop). */
>> vect_unpromoted_value unprom0[2];
>> + enum optab_subtype subtype = optab_vector;
>> if (!vect_widened_op_tree (vinfo, mult_vinfo, MULT_EXPR, WIDEN_MULT_EXPR,
>> - false, 2, unprom0, &half_type))
>> + false, 2, unprom0, &half_type, &subtype))
>> + return NULL;
>> +
>> + if (subtype == optab_vector_mixed_sign
>> + && TYPE_UNSIGNED (unprom_mult.type)
>> + && TYPE_PRECISION (half_type) * 4 > TYPE_PRECISION (unprom_mult.type))
>> return NULL;
>
> Isn't the final condition here instead that TYPE1 is narrower than TYPE2?
> I.e. we need to reject the case in which we multiply a signed and an
> unsigned value to get a (logically) signed result, but then zero-extend
> it (rather than sign-extend it) to the precision of the addition.
>
> That would make the test:
>
> if (subtype == optab_vector_mixed_sign
> && TYPE_UNSIGNED (unprom_mult.type)
> && TYPE_PRECISION (unprom_mult.type) < TYPE_PRECISION (type))
> return NULL;
>
> instead.
And folding that into the existing test gives:
/* If there are two widening operations, make sure they agree on the sign
of the extension. The result of an optab_vector_mixed_sign operation
is signed; otherwise, the result has the same sign as the operands. */
if (TYPE_PRECISION (unprom_mult.type) != TYPE_PRECISION (type)
&& (subtype == optab_vector_mixed_sign
? TYPE_UNSIGNED (unprom_mult.type)
: TYPE_SIGN (unprom_mult.type) != TYPE_SIGN (half_type)))
return NULL;
Thanks,
Richard
next prev parent reply other threads:[~2021-06-22 11:16 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 17:38 Tamar Christina
2021-05-05 17:38 ` [PATCH 2/4]AArch64: Add support for sign differing dot-product usdot for NEON and SVE Tamar Christina
2021-05-10 16:49 ` Richard Sandiford
2021-05-25 14:57 ` Tamar Christina
2021-05-26 8:50 ` Richard Sandiford
2021-05-05 17:39 ` [PATCH 3/4][AArch32]: Add support for sign differing dot-product usdot for NEON Tamar Christina
2021-05-05 17:42 ` FW: " Tamar Christina
[not found] ` <VI1PR08MB5325B832EE3BB6139886C0E9FF259@VI1PR08MB5325.eurprd08.prod.outlook.com>
2021-05-25 15:02 ` Tamar Christina
2021-05-26 10:45 ` Kyrylo Tkachov
2021-05-06 9:23 ` Christophe Lyon
2021-05-06 9:27 ` Tamar Christina
2021-05-05 17:39 ` [PATCH 4/4]middle-end: Add tests middle end generic tests for sign differing dotproduct Tamar Christina
[not found] ` <VI1PR08MB532511701573C18A33AC6291FF259@VI1PR08MB5325.eurprd08.prod.outlook.com>
2021-05-25 15:01 ` FW: " Tamar Christina
[not found] ` <11s2181-8856-30rq-26or-84q8o7qrr2o@fhfr.qr>
2021-05-26 8:48 ` Tamar Christina
2021-06-14 12:08 ` Tamar Christina
2021-05-07 11:45 ` [PATCH 1/4]middle-end Vect: Add support for dot-product where the sign for the multiplicant changes Richard Biener
2021-05-07 12:42 ` Tamar Christina
2021-05-10 11:39 ` Richard Biener
2021-05-10 12:58 ` Tamar Christina
2021-05-10 13:29 ` Richard Biener
2021-05-25 14:57 ` Tamar Christina
2021-05-26 8:56 ` Richard Biener
2021-06-02 9:28 ` Tamar Christina
2021-06-04 10:12 ` Tamar Christina
2021-06-07 10:10 ` Richard Sandiford
2021-06-14 12:06 ` Tamar Christina
2021-06-21 8:11 ` Tamar Christina
2021-06-22 10:56 ` Richard Sandiford
2021-06-22 11:16 ` Richard Sandiford [this message]
2021-07-12 9:18 ` Tamar Christina
2021-07-12 9:39 ` Richard Sandiford
2021-07-12 9:56 ` Tamar Christina
2021-07-12 10:25 ` Richard Sandiford
2021-07-12 12:29 ` Tamar Christina
2021-07-12 14:55 ` Richard Sandiford
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