[PATCH] D142656: [SVE][codegen] Add pattern for SVE multiply-add accumulate

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

In D142656#4096082 <https://reviews.llvm.org/D142656#4096082>, @david-arm wrote:

> Hi @SjoerdMeijer, in @sushgokh's defence there is precedent for some of the changes in this patch - by changing from SVE_4_Op_Pat to SVE_4_Mad_Op_Pat we are able to set the AddedComplexity field to the pattern, which is not dissimilar to SVE_3_Op_Pat_SelZero or SVE_3_Op_Pat_Shift_Imm_SelZero, i.e.
>
>   let AddedComplexity = 1 in {
>   class SVE_3_Op_Pat_SelZero<ValueType vtd, SDPatternOperator op, ValueType vt1,
>                      ValueType vt2, ValueType vt3, Instruction inst>
>   : Pat<(vtd (vtd (op vt1:$Op1, (vselect vt1:$Op1, vt2:$Op2, (SVEDup0)), vt3:$Op3))),
>         (inst $Op1, $Op2, $Op3)>;
>   
>   class SVE_3_Op_Pat_Shift_Imm_SelZero<ValueType vtd, SDPatternOperator op,
>                                        ValueType vt1, ValueType vt2,
>                                        Operand vt3, Instruction inst>
>   : Pat<(vtd (op vt1:$Op1, (vselect vt1:$Op1, vt2:$Op2, (SVEDup0)), (i32 (vt3:$Op3)))),
>         (inst $Op1, $Op2, vt3:$Op3)>;
>   }
>
> What I don't fully understand is why the complexity has to be so high, since it suggests there are multiple competing patterns and it might be useful to understand what they are. I admit that `AArch64mul_p_firstOpndWithSingleUse` looks a bit unusual and I'm not sure that we should be checking for explicit opcodes such as TokenFactor, etc.

I am not agains it, just trying to understand it. :)
If this is only about the complexity, can we do this differently?


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https://reviews.llvm.org/D142656