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Date: Mon, 01 Jul 2019 16:32:00 -0000
From: James Greenhalgh <james.greenhalgh@arm.com>
To: Dennis Zhang <Dennis.Zhang@arm.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>, nd <nd@arm.com>,	Richard Earnshaw <Richard.Earnshaw@arm.com>,	Marcus Shawcroft <Marcus.Shawcroft@arm.com>
Subject: Re: [PATCH][AArch64] Remove constraint strings from define_expand constructs in the back end
Message-ID: <20190701163207.GB23283@arm.com>
References: <76753858-bb8d-2016-56c8-fc883fcd7f9a@arm.com>
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On Mon, Jun 24, 2019 at 04:33:40PM +0100, Dennis Zhang wrote:
> Hi,
> 
> A number of AArch64 define_expand patterns have specified constraints 
> for their operands. But the constraint strings are ignored at expand 
> time and are therefore redundant/useless. We now avoid specifying 
> constraints in new define_expands, but we should clean up the existing 
> define_expand definitions.
> 
> For example, the constraint "=w" is removed in the following case:
> (define_expand "sqrt<mode>2"
>    [(set (match_operand:GPF_F16 0 "register_operand" "=w")
> The "" marks with an empty constraint in define_expand are removed as well.
> 
> The patch is tested with the build configuration of 
> --target=aarch64-none-linux-gnu, and it passes gcc/testsuite.

This is OK for trunk.

Thanks,
James

> gcc/ChangeLog:
> 
> 2019-06-21  Dennis Zhang  <dennis.zhang@arm.com>
> 
> 	* config/aarch64/aarch64-simd.md: Remove redundant constraints
> 	from define_expand.
> 	* config/aarch64/aarch64-sve.md: Likewise.
> 	* config/aarch64/aarch64.md: Likewise.
> 	* config/aarch64/atomics.md: Likewise.