roy rosen schrieb:
> Thanks Georg,
> The -fdump-rtl-combine-details really helps.
> Regarding implementing it through cbranchhi4, this is not enough for
> me because when getting to this pattern the operands have already been
> expanded, and I am trying to prevent that.
> Is there a way around it?
>
> Roy.
>
> 2010/10/25 Georg Lay <a...@gjlay.de>:
>> roy rosen schrieb:
>>> In my port I get to such a situation:
>>>
>>> (insn 60 59 61 4 a.c:65 (set (subreg:SI (reg:HI 129 [ __prephitmp_4 ]) 0)
>>> (zero_extract:SI (subreg:SI (reg/v:DI 138 [ v4hi1 ]) 4)
>>> (const_int 16 [0x10])
>>> (const_int 16 [0x10]))) 53 {extzv} (nil))
>>>
>>> (insn 61 60 62 4 a.c:65 (set (reg:BI 159)
>>> (gtu:BI (reg:HI 129 [ __prephitmp_4 ])
>>> (reg/v:HI 143 [ usiThresh ]))) 94 {cmprr_hi_gtu} (nil))
>>>
>>> The patterns for these are:
>>>
>>> (define_insn "extzv"
>>> [(set (match_operand:SI 0 "register_operand" "=d")
>>> (zero_extract:SI (match_operand:SI 1 "register_operand" "d")
>>> (match_operand:SI 2 "immediate_operand" "U06")
>>> (match_operand:SI 3 "immediate_operand" "U06")))]
>>> ""
>>> "extractua\t %2, %3, %1, %0 %!"
>>> )
>>>
>>> and
>>>
>>> (define_insn "cmprr_hi_<code>"
>>> [(set (match_operand:BI 0 "register_operand" "=c")
>>> (any_cond_rr:BI (match_operand:HI 1 "register_operand" "d")
>>> (match_operand:HI 2 "register_operand" "d")))]
>>> ""
>>> "cmp<code> %2.L, %1.L, %0:%I0 %!"
>>> )
>>>
>>> I want the combiner to combine both insns since I have an intruction
>>> which can compare from an HI partial register.
>>> I am trying to write an insn pattern for that but the combiner does not use
>>> i.
>>> I thought about something like:
>>>
>>> (define_insn "cmprr_hi_<code>_1"
>>> [(set (match_operand:BI 0 "register_operand" "=c")
>>> (any_cond_rr:BI (zero_extract:SI (match_operand:DI 1
>>> "register_operand" "d")
>>> (const_int 16) (const_int 16))
>>> (match_operand:HI 2 "register_operand" "d")))]
>>> ""
>>> "cmp<code> %2.L, %1.L, %0:%I0 %!"
>>> )
>>>
>>> but it does not work.
>>> Can someone please help?
>> To compare HI there are standard insns "cstorehi4" and "cbranchhi4". Maybe
>> you
>> wand to implement an insn/expander that supports them.
>>
>> As far as the combiner is concerned: Look at combiner dumps with
>> -fdump-rtl-combine-details if the combiner tries to combine these insns and
>> the
>> way it does this. It's useless to write patterns that combine will never
>> try...
>>
>> Moreover, the first pattern looks rather like an "insv" than an extract. So
>> it
>> might help to write proper insv-expanders.
Hard to tell without seeing what combine tries and how insv expands.
In some situations I get better results by expanding insv algebraically, i.e. as
a combination of AND and IOR stuff. This is a little bit tedious but allows the
output operand to be different from the insertion dest.
Georg Lay
