[PATCH] D127880: [RISCV] Avoid reducing etype just to initialize lane 0 of an undef vector

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp:935
+       (CurInfo.hasZeroAVL() && Require.hasZeroAVL()))) {
+    auto *VRegDef = MRI->getVRegDef(MI.getOperand(1).getReg());
+    if (VRegDef && VRegDef->isImplicitDef() &&
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craig.topper wrote:
> I wonder if we should call elideCopies here like we do when we look for implicit def for tail policy. 
Hmm it doesn't look like any existing lit tests need the elideCopies call in other location. So I'm not sure if that's still needed. It might be a left over from when we did vsetvli insertion right after SelectionDAG.


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https://reviews.llvm.org/D127880