[PATCH] D69842: [InstCombine] canonicalize shift+logic+shift to reduce dependency chain

[Sanjay Patel via Phabricator via llvm-commits]

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


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp:321
+  auto matchFirstShift = [&](Value *V) {
+    return match(V, m_OneUse(m_Shift(m_Value(X), m_APInt(C0)))) &&
+           cast<BinaryOperator>(V)->getOpcode() == ShiftOpcode &&
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lebedev.ri wrote:
> This innermost shift only has to be one-use iff `Y` is not constant.
Good point - I'll make it a TODO for this patch, and we can follow-up with an enhancement.


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  https://reviews.llvm.org/D69842/new/

https://reviews.llvm.org/D69842