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Date: Wed, 05 Aug 2015 16:08:00 -0000
From: Alan Lawrence <alan.lawrence@arm.com>
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To: Richard Biener <richard.guenther@gmail.com>
CC: Michael Collison <michael.collison@linaro.org>,  gcc Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Optimize certain end of loop conditions into min/max operation
References: <55B5A884.4060105@linaro.org> <CAFiYyc1ObfTFaChzLiAezxEzVziVFnDzCTBhvS0v975-xXRosw@mail.gmail.com>
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Richard Biener wrote:

> Furthermore it doesn't work for three such ops which would require
> an additional pattern like
>=20
>  (simplfiy
>   (bit_and:c (op @0 (min @1 @2)) (op @0 @3))
>   (op @0 (min (min @1 @2) @3))))
>=20
> if that's profitable?

Shouldn't that be just a case of binding @1 in the original pattern:

>> +/* Transform (@0 < @1 and @0 < @2) to use min */
>> +(for op (lt le)
>> +(simplify
>> +(bit_and:c (op @0 @1) (op @0 @2))
 >> +(if (INTEGRAL_TYPE_P (TREE_TYPE (@0)))
 >> +(op @0 (min @1 @2)))))

to (min @1 @2) in your three-way pattern, @2 in the original to @3 in yours=
, and=20
@0 to @0 ?

Or is @1 not allowed to bind to a 'min' ?


Secondly: should/can Michael's fix reference PR57600 ?

Cheers,
Alan