Robin Dapp via Gcc-patches writes:
> Thanks for looking at it in detail.
>
>> Yeah, I think this is potentially a blocker for propagating A into B
>> when A is used elsewhere. Combine is able to combine A and B while
>> keeping A in parallel with the result. I think either fwprop would
>> need t
Thanks for looking at it in detail.
> Yeah, I think this is potentially a blocker for propagating A into B
> when A is used elsewhere. Combine is able to combine A and B while
> keeping A in parallel with the result. I think either fwprop would
> need to try that too, or it would need to be rest
Robin Dapp writes:
> Hi Richard,
>
> I did some testing with the attached v2 that does not restrict to UNARY
> anymore. As feared ;) there is some more fallout that I'm detailing below.
>
> On Power there is one guality fail (pr43051-1.c) that I would take
> the liberty of ignoring for now.
>
> O
> Thanks for giving it a go. Can you post the latest version of the
> regpressure patch too? The previous on-list version I could find
> seems to be too old.
Oh, sure, attached. Apologies, I added the regpressure_same_class
convenience helper but forgot to re-send it.
Regards
Robin
>From d3f
Robin Dapp writes:
> Hi Richard,
>
> I did some testing with the attached v2 that does not restrict to UNARY
> anymore. As feared ;) there is some more fallout that I'm detailing below.
>
> On Power there is one guality fail (pr43051-1.c) that I would take
> the liberty of ignoring for now.
>
> O
Hi Richard,
I did some testing with the attached v2 that does not restrict to UNARY
anymore. As feared ;) there is some more fallout that I'm detailing below.
On Power there is one guality fail (pr43051-1.c) that I would take
the liberty of ignoring for now.
On x86 there are four fails:
- con
> I imagine doing it in reverse postorder would still make sense.
>
> But my point was that, for the current fwprop limitation of substituting
> into exactly one use of a register, we can check whether that use is
> the *only* use of register.
>
> I.e. if we substitute:
>
> A: (set (reg R1) (f
Robin Dapp writes:
>> So I don't think I have a good feel for the advantages and disadvantages
>> of doing this. Robin's analysis of the aarch64 changes was nice and
>> detailed though. I think the one that worries me most is the addressing
>> mode one. fwprop is probably the first chance we ge
> So I don't think I have a good feel for the advantages and disadvantages
> of doing this. Robin's analysis of the aarch64 changes was nice and
> detailed though. I think the one that worries me most is the addressing
> mode one. fwprop is probably the first chance we get to propagate adds
> in
e of combine's work a bit towards
>> the front of the RTL pipeline?
>>
>> Regards
>> Robin
>>
>> Subject: [PATCH] fwprop: Allow UNARY_P and check register pressure.
>>
>> This patch enables the forwarding of UNARY_P sources. As
eline?
Regards
Robin
Subject: [PATCH] fwprop: Allow UNARY_P and check register pressure.
This patch enables the forwarding of UNARY_P sources. As this
involves potentially replacing a vector register with a scalar register
the ira_hoist_pressure machinery is used to calculate the change in
reg
Ping. I refined the code and some comments a bit and added a test
case.
My question in general would still be: Is this something we want
given that we potentially move some of combine's work a bit towards
the front of the RTL pipeline?
Regards
Robin
Subject: [PATCH] fwprop: Allow UNARY_
Hi,
originally inspired by the wish to transform
vmv v3, a0 ; = vec_duplicate
vadd.vv v1, v2, v3
into
vadd.vx v1, v2, a0
via fwprop for riscv, this patch enables the forward propagation
of UNARY_P sources.
As this involves potentially replacing a vector register with
a scalar register the
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