[PATCH] D41446: [TableGen][AsmMatcherEmitter] Generate assembler checks for tied operands

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen marked an inline comment as done.
sdesmalen added inline comments.


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Comment at: utils/TableGen/AsmMatcherEmitter.cpp:969
+  const auto &CGIOperands = getResultInst()->Operands;
+  for (const auto &CGIOp : CGIOperands) {
+    const auto &CGIConstraints = CGIOp.Constraints;
----------------
fhahn wrote:
> I think the loop body here can be simplified by using `CGIOp.getTiedRegister();` rather than checking the constraints here:
> 
> 
> ```
> +    int TiedReg = CGIOp.getTiedRegister();
> +    if (TiedReg == -1)
> +      continue;
> +
> +    Optional<size_t> LHSIdx = getAsmOperandIdx(AsmOperands, CGIOp.Name);
> +    Optional<size_t> RHSIdx = getAsmOperandIdx(AsmOperands, CGIOperands[TiedReg].Name);
> +    // Skipping operands with constraint but no reference in the
> +    // AsmString. No need to throw a warning, as it's normal to have
> +    // a $dst operand in the outs dag that is constrained to a $src
> +    // operand in the ins dag but that does not appear in the AsmString.
> +    if (!LHSIdx || !RHSIdx)
> +      continue;
> +
> +    // Add the constraint. Using min/max as we consider constraint
> +    // pair {A,B} and {B,A} the same
> +    size_t AddMnemonicIdx = HasMnemonicFirst;
> +    AsmOperandTiedConstraints.emplace_back(
> +        std::min(*LHSIdx, *RHSIdx) + AddMnemonicIdx,
> +        std::max(*LHSIdx, *RHSIdx) + AddMnemonicIdx);
> +  }
> ```
Thanks Florian, I've implemented your suggestion.


https://reviews.llvm.org/D41446