[llvm] [VPlan] Explicitly replicate VPInstructions by VF. (PR #155102)

[Florian Hahn via llvm-commits]

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@@ -1287,6 +1266,12 @@ bool VPInstruction::onlyFirstLaneUsed(const VPValue *Op) const {
   case VPInstruction::Broadcast:
   case VPInstruction::ReductionStartVector:
     return true;
+  case VPInstruction::BuildStructVector:
+  case VPInstruction::BuildVector:
+    // Before replicating by VF, Build(Struct)Vector uses all lanes of the
+    // operand, after replicating its operands only the first lane is used.
+    // Before replicating, it will only have a single operand.
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fhahn wrote:

Done, thanks

https://github.com/llvm/llvm-project/pull/155102