[PATCH] D121881: [RISCV][RVV] Select unmasked TU RVV pseudos in a DAG post-process

[Fraser Cormack via Phabricator via llvm-commits]

frasercrmck added a comment.

I'm glad we don't need to add dummy pseudos for this to work :)

This is now looking good, thank you: just to check - there's no way to //dynamically// check whether the `TU` pseudo exists in TableGen? That would remove the need for `HasTU` which I'd find a bit cleaner.



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Comment at: llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp:2278
+        return false;
+      // Use TA if tie-operand is IMPLICIT_DEF
+      if (!N->getOperand(0).isUndef())
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This comment should probably be inverted. Something like "if the merge operand //isn't// IMPLICIT_DEF then we //can't// use TA"?


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Comment at: llvm/lib/Target/RISCV/RISCVInstrInfoVPseudos.td:427
+// This is a placeholder for pseudos which don't have a TU
+def PseudoNoTU: Pseudo<(outs), (ins), []> {
+  let hasSideEffects = 0;
----------------
Can get rid of this now it's unused?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D121881/new/

https://reviews.llvm.org/D121881