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From: Bernd Edlinger <bernd.edlinger@hotmail.de>
To: Wilco Dijkstra <Wilco.Dijkstra@arm.com>,
	"gcc-patches@gcc.gnu.org"	<gcc-patches@gcc.gnu.org>
Cc: Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
	Richard Earnshaw	<Richard.Earnshaw@arm.com>,
	Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>, nd	<nd@arm.com>
Subject: Re: [PATCH, ARM] Further improve stack usage in sha512, part 2 (PR 77308)
Date: Tue, 20 Dec 2016 18:52:00 -0000	[thread overview]
Message-ID: <AM4PR0701MB2162C4764A52C576446FF1D3E4900@AM4PR0701MB2162.eurprd07.prod.outlook.com> (raw)
In-Reply-To: <AM5PR0802MB2610F553CE14E5C0EFD1371783900@AM5PR0802MB2610.eurprd08.prod.outlook.com>

On 12/20/16 16:09, Wilco Dijkstra wrote:
> Bernd Edlinger wrote:
>> this splits the *arm_negdi2, *arm_cmpdi_insn and *arm_cmpdi_unsigned
>> also at split1 except for TARGET_NEON and TARGET_IWMMXT.
>>
>> In the new test case the stack is reduced to about 270 bytes, except
>> for neon and iwmmxt, where this does not change anything.
>
> This looks odd:
>
> -    operands[2] = gen_lowpart (SImode, operands[2]);
> +    if (can_create_pseudo_p ())
> +      operands[2] = gen_reg_rtx (SImode);
> +    else
> +      operands[2] = gen_lowpart (SImode, operands[2]);
>
> Given this is an SI mode scratch, do we need the else part at all? It seems wrong
> to ask for the low part of an SI mode operand...
>

Yes, I think that is correct.

> Other than that it looks good to me, but I can't approve.
>
> As a result of your patches a few patterns are unused now. All the Thumb-2 iordi_notdi*
> patterns cannot be used anymore. Also I think arm_cmpdi_zero never gets used - a DI
> mode compare with zero is always split into ORR during expand.
>

I did not change anything for -mthumb -mfpu=neon for instance.
Do you think that iordi_notdi* is never used also for that
configuration?

And if the arm_cmpdi_zero is never expanded, isn't it already
unused before my patch?


Bernd.

  reply	other threads:[~2016-12-20 18:17 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-18 13:32 Bernd Edlinger
2016-12-20 15:29 ` Wilco Dijkstra
2016-12-20 18:52   ` Bernd Edlinger [this message]
2016-12-21 15:20     ` Wilco Dijkstra
2017-04-29 20:09 ` Bernd Edlinger
2017-05-12 16:55   ` [PING**2] " Bernd Edlinger
2017-06-01 16:02     ` [PING**3] " Bernd Edlinger
     [not found]     ` <d2793404-f5c5-fe88-cb16-51a38ffa05c0@hotmail.de>
2017-06-14 12:39       ` [PING**4] " Bernd Edlinger
2017-09-04 16:20   ` Kyrill Tkachov

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