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Subject: Re: [PATCH 11/25] Simplify vec_merge according to the mask.
To: <gcc-patches@gcc.gnu.org>, <richard.sandiford@arm.com>
References: <cover.1536144068.git.ams@codesourcery.com> <333c6a5ad2f1c56613c4734a830fc5d8214061d9.1536144068.git.ams@codesourcery.com> <87pnxc4hp0.fsf@arm.com> <047d2b64-5a08-599c-9529-3e1270c38791@codesourcery.com> <875zys433p.fsf@arm.com>
From: Andrew Stubbs <ams@codesourcery.com>
Message-ID: <2b7abb07-b9df-71a1-056c-2985067e74d3@codesourcery.com>
Date: Wed, 26 Sep 2018 17:06:00 -0000
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On 26/09/18 17:48, Richard Sandiford wrote:
> Andrew Stubbs <ams@codesourcery.com> writes:
>> +  /* Nested vec_merge.  */
>> +  rtx nvm = gen_rtx_VEC_MERGE (mode, vm1, vm2, mask1);
>> +  ASSERT_EQ (vm1, simplify_merge_mask (nvm, mask1, 0));
>> +  ASSERT_EQ (vm2, simplify_merge_mask (nvm, mask1, 1));
> 
> Think the last two should simplify to op0 and op3, which I guess
> means recursing on the "return XEXP (x, op);"

I thought about doing that, but I noticed that, for example, 
simplify_gen_unary does not recurse into its operand. Is that an 
omission, or is it expected that those operands will already have been 
simplified?

Andrew