[PATCH] D138872: [InstCombine] canonicalize trunc + insert as bitcast + shuffle, part 1

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

Why is a trunc, and an one-use at that, a requirement?
It seems like looking through trunc should either be a follow-up for this fold, or for shuffle combining.



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Comment at: llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp:1525
+  uint64_t IndexC;
+  if (!VTy || !match(InsElt.getOperand(1), m_OneUse(m_Trunc(m_Value(T)))) ||
+      !match(InsElt.getOperand(2), m_ConstantInt(IndexC)) ||
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Why is a trunc, and an one-use at that, a requirement?
Please at least add a FIXME.


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  https://reviews.llvm.org/D138872/new/

https://reviews.llvm.org/D138872