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Re: Fix PR 49014
- From: Bernd Schmidt <bernds at codesourcery dot com>
- To: Andrey Belevantsev <abel at ispras dot ru>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, "Vladimir N. Makarov" <vmakarov at redhat dot com>
- Date: Thu, 07 Jul 2011 19:08:25 +0200
- Subject: Re: Fix PR 49014
- References: <4DDCBC02.7020002@ispras.ru> <4DDD1528.8060200@codesourcery.com> <4DDD2043.1080703@ispras.ru> <4DDD20CE.4000707@codesourcery.com> <4DDE5657.4000601@ispras.ru> <4E0DDEBA.5000804@ispras.ru>
On 07/01/11 16:50, Andrey Belevantsev wrote:
> On 26.05.2011 17:32, Andrey Belevantsev wrote:
>> On 25.05.2011 19:31, Bernd Schmidt wrote:
>>> On 05/25/2011 03:29 PM, Andrey Belevantsev wrote:
>>>> I think the hook is a better idea than the attribute because nobody
>>>> will
>>>> care to mark all offending insns with an attribute.
>>>
>>> I don't know. IIRC when I looked at sh or whatever the broken port was,
>>> it was only two insns - there would still be some value in being able to
>>> assert that all other insns have a reservation.
>> OK, I will take a look on x86-64 and will get back with more information.
>>
>> Andrey
> So, I have made an attempt to bootstrap on x86-64 with the extra assert
> in selective scheduling that assumes the DFA state always changes when
> issuing a recog_memoized >=0 insn (patch attached). Indeed, there are
> just a few general insns that don't have proper reservations. However,
> it was a surprise to me to see that almost any insn with SSE registers
> fails this assert and thus does not get properly scheduled.
Probably because it's picking a scheduling description for an old CPU?
With "-mcpu=pentium" probably none of the newer patterns has a reservation.
That may scupper any plans to use this attribute on i386.
> Overall, the work on fixing those seems doable, it took just a day to
> get the compiler bootstrapped (of course, the testsuite may bring much
> more issues). So, if there is an agreement on marking a few offending
> insns with the new attribute, we can proceed with the help of somebody
> from the x86 land on fixing those and researching for other targets.
+ (set (attr "nondfa_insn") (if_then_else (eq_attr "alternative"
"3,4,5,6") (const_int 1) (const_int 0)))
I think this shouldn't use (const_int x); you want to be able to write
(set_attr "nondfa_insn" "0,0,0,1,1,1,1")
Bernd