[llvm] [VPlan] Compute scalar cost based on VPlan0 instead of legacy CM. (PR #196845)

[Florian Hahn via llvm-commits]

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@@ -1480,15 +1505,39 @@ InstructionCost VPInstruction::computeCost(ElementCount VF,
     return getCostForRecipeWithOpcode(
         getOpcode(),
         vputils::onlyFirstLaneUsed(this) ? ElementCount::getFixed(1) : VF, Ctx);
+  case Instruction::ExtractValue:
+  case Instruction::FNeg:
+  case Instruction::Freeze:
+    if (!VF.isScalar() || !getUnderlyingValue())
+      return 0;
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fhahn wrote:

Updated to break and moved the assert outside the switch, so it should still be covered.

https://github.com/llvm/llvm-project/pull/196845