------- Comment #3 from dougkwan at google dot com 2009-05-15 08:28 -------
Subject: Re: Long long comparison optimized away
incorrectly in Thumb code.
I am running regression tests and will submit a patch tomorrow morning
after that.
-Doug
2009/5/15 ramana at gcc dot gnu dot org <gcc-bugzi...@gcc.gnu.org>:
>
>
> ------- Comment #2 from ramana at gcc dot gnu dot org 2009-05-15 08:26
> -------
> (In reply to comment #1)
>> This is caused by a typo in arm.md.
>>
>> (define_insn "cstoresi_nltu_thumb1"
>> [(set (match_operand:SI 0 "s_register_operand" "=l,l")
>> (neg:SI (gtu:SI (match_operand:SI 1 "s_register_operand" "l,*h")
>> (match_operand:SI 2 "thumb1_cmp_operand"
>> "lI*h,*r"))))]
>> "TARGET_THUMB1"
>> "cmp\\t%1, %2\;sbc\\t%0, %0, %0"
>> [(set_attr "length" "4")]
>> )
>>
>> The instruction cstoresi_nltu_thumb1 is used to compute the expression -(x <
>> y)
>> where x and y are unsigned SI-type values. The operand of the NEG RTX should
>> be a LTU RTX instead of a GTU RTX. The incorrected RTX code caused a later
>> CSE
>> pass to substitute this pattern:
>>
>> (set x
>> (neg (gtu a b))) <=== cstoresi_nltu_thumb1
>> (set y (neg x))
>>
>> with
>>
>> (set y (gtu a b))
>>
>> I tried fixing the RTX code and the test case passed.
>>
>
> This looks correct. Please submit a patch to gcc-patc...@.
>
>
> --
>
> ramana at gcc dot gnu dot org changed:
>
> What |Removed |Added
> ----------------------------------------------------------------------------
> Status|UNCONFIRMED |NEW
> Ever Confirmed|0 |1
> Last reconfirmed|0000-00-00 00:00:00 |2009-05-15 08:26:09
> date| |
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40153
>
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40153
