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From: Richard Sandiford <richard.sandiford@arm.com>
To: "Andre Vieira \(lists\)" <andre.simoesdiasvieira@arm.com>
Mail-Followup-To: "Andre Vieira \(lists\)" <andre.simoesdiasvieira@arm.com>,
 Christophe Lyon <christophe.lyon@foss.st.com>, gcc-patches@gcc.gnu.org,
 Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>, richard.sandiford@arm.com
Cc: Christophe Lyon <christophe.lyon@foss.st.com>, gcc-patches@gcc.gnu.org,
 Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
Subject: Re: [PATCH v3 06/15] arm: Fix mve_vmvnq_n_<supf><mode> argument mode
References: <20220113145645.4077141-1-christophe.lyon@foss.st.com>
 <20220113145645.4077141-7-christophe.lyon@foss.st.com>
 <c2c7a5ea-9a2b-f5ec-c8c4-aef3e0a6fc71@arm.com>
Date: Thu, 20 Jan 2022 10:45:54 +0000
In-Reply-To: <c2c7a5ea-9a2b-f5ec-c8c4-aef3e0a6fc71@arm.com> (Andre Vieira's
 message of "Wed, 19 Jan 2022 19:03:05 +0000")
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"Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com> writes:
> On 13/01/2022 14:56, Christophe Lyon via Gcc-patches wrote:
>> The vmvnq_n* intrinsics and have [u]int[16|32]_t arguments, so use
>> <V_elem> iterator instead of HI in mve_vmvnq_n_<supf><mode>.
>>
>> 2022-01-13  Christophe Lyon  <christophe.lyon@foss.st.com>
>>
>> 	gcc/
>> 	* config/arm/mve.md (mve_vmvnq_n_<supf><mode>): Use V_elem mode
>> 	for operand 1.
>>
>> diff --git a/gcc/config/arm/mve.md b/gcc/config/arm/mve.md
>> index 171dd384133..5c3b34dce3a 100644
>> --- a/gcc/config/arm/mve.md
>> +++ b/gcc/config/arm/mve.md
>> @@ -617,7 +617,7 @@ (define_insn "mve_vcvtaq_<supf><mode>"
>>   (define_insn "mve_vmvnq_n_<supf><mode>"
>>     [
>>      (set (match_operand:MVE_5 0 "s_register_operand" "=w")
>> -	(unspec:MVE_5 [(match_operand:HI 1 "immediate_operand" "i")]
>> +	(unspec:MVE_5 [(match_operand:<V_elem> 1 "immediate_operand" "i")]
>>   	 VMVNQ_N))
>>     ]
>>     "TARGET_HAVE_MVE"
>
> While fixing this it might be good to fix the constraint and predicate 
> inspired by "DL" and "neon_inv_logic_op2" respectively. This would avoid 
> the compiler generating wrong assembly, and instead it would probably 
> lead to the compiler using a load literal.

FWIW: for cases like this, I think it's better to define a predicate
only (not a constraint).  By design, the only time that constraints
are used independently of predicates is during RA, and there's nothing
that RA can/should do for immediate operands.

Thanks,
Richard