[PATCH] D34077: DAGCombine: Combine BUILD_VECTOR to TRUNCATE

[Zvi Rackover via Phabricator via llvm-commits]

zvi added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:14192
+  // TODO: Allow undef elements in some cases?
+  if (any_of(make_range(N->op_begin(), N->op_end()), [VT](SDValue Op) {
+        return Op.getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
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delena wrote:
> Code simplification:
> any_of(N->operands() ..
There is no SDNode::operands(). I was thinking of adding one as a follow-up commit if it makes sense.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:14289
 
+  if (SDValue V = reduceBuildVecToTrunc(N))
+    return V;
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delena wrote:
> I'd put isDesirable..() here, before call to reduceBuildVecToTrunc(), with N node as parameter.
But we don't know in advance what will be the truncate's operand type and result type. Need to some analysis first.


https://reviews.llvm.org/D34077