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Re: GCC4.3.4 downside against GCC3.4.4 on mips?
- From: "Amker.Cheng" <amker dot cheng at gmail dot com>
- To: gcc at gcc dot gnu dot org
- Cc: Richard Guenther <richard dot guenther at gmail dot com>
- Date: Mon, 12 Jul 2010 09:32:23 +0800
- Subject: Re: GCC4.3.4 downside against GCC3.4.4 on mips?
- References: <AANLkTin4axeTjBjWaSmakG2um2MzAqy_tCLpDHzUlTnb@mail.gmail.com> <3ada5fe2e4b15ae3fefa95747429b841@shell.sh.cvut.cz> <AANLkTimoJoMWDVveYJGXJzK-Tu_KWMIWXe-MVgNlLIU2@mail.gmail.com> <4BFE597A.5080303@gnu.org> <AANLkTimG6EXeQj6nAIC2MUQuHuTGSuKXMBytQRggzOro@mail.gmail.com>
>>>
>>> while GCC3.4.4 treats the long long multiplication just like simple
>>> ones, which generates only one
>>> mult insn for each statement, like
>>>
>>> In my understanding, It‘s not necessary using three mult insn to implement
>>> long long mult, since the operands are converted from int type.
>>
>> This is more helpful. ?It is a known case in which GCC 4.x generates worse
>> code.
>
> Should be fixed with 4.6.
Hi, I tested this problem on GCC4.6 snapshot, and it works.
But I could not find the specific patch or record in buglist,
could you help? thanks very much.
--
Best Regards.