From: Richard Biener <richard.guenther@gmail.com>
To: Jeff Law <law@redhat.com>
Cc: Joseph Myers <joseph@codesourcery.com>,GCC Patches
<gcc-patches@gcc.gnu.org>
Subject: Re: [RFC][PR target/39726 P4 regression] match.pd pattern to do type narrowing
Date: Tue, 03 Feb 2015 11:39:00 -0000 [thread overview]
Message-ID: <8B8165F1-1BF4-41EA-B680-D2C890D36C5B@gmail.com> (raw)
In-Reply-To: <54CFC2AF.1040405@redhat.com>
On February 2, 2015 7:32:15 PM CET, Jeff Law <law@redhat.com> wrote:
>On 02/02/15 01:57, Richard Biener wrote:
>>>
>>> The nice thing about wrapping the result inside a convert is the
>types for
>>> the inner operations will propagate from the type of the inner
>operands,
>>> which is exactly what we want. We then remove the hack assigning
>type and
>>> instead the original type will be used for the outermost convert.
>>
>> It's not even a hack but wrong ;) Correct supported syntax is
>>
>> + (with { tree type0 = TREE_TYPE (@0); }
>> + (convert:type0 (bit_and (inner_op @0 @1) (convert @3)))))))
>>
>> Thus whenever the generator cannot auto-guess a type (or would guess
>> the wrong one) you can explicitely specify a type to convert to.
>I found that explicit types were ignored in some cases. It was
>frustrating to say the least.
Huh, that would be a bug. Do you have a pattern where that happens?
Richard.
But I think I've got this part doing
>what
>I want without the hack.
>
>>
>> Why do you restrict this to GENERIC? On GIMPLE you'd eventually
>> want to impose some single-use constraints as the result with all
>> the conversions won't really be unconditionally "better"?
>That was strictly because of the mismatch between the resulting type
>and
>how it was later used. That restriction shouldn't be needed anymore.
>
>Jeff
next prev parent reply other threads:[~2015-02-03 11:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-31 8:53 Jeff Law
2015-02-01 0:47 ` Joseph Myers
2015-02-01 5:46 ` Jeff Law
2015-02-02 8:57 ` Richard Biener
2015-02-02 18:32 ` Jeff Law
2015-02-03 11:39 ` Richard Biener [this message]
2015-02-09 7:15 ` Jeff Law
2015-02-09 13:42 ` Richard Biener
2015-02-09 18:33 ` Jeff Law
2015-02-02 16:59 ` Joseph Myers
2015-02-02 18:04 ` Jeff Law
2015-02-03 7:20 ` Jeff Law
2015-02-03 12:23 ` Joseph Myers
2015-02-08 7:43 ` Jeff Law
2015-02-11 6:43 ` Jeff Law
2015-02-11 11:16 ` Richard Biener
2015-02-11 15:56 ` Jeff Law
2015-02-11 16:06 ` Jakub Jelinek
2015-02-11 17:13 ` Joseph Myers
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