[llvm] [VPlan] Use VPInstructionWithType for uniform casts. (PR #140623)

[Florian Hahn via llvm-commits]

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@@ -1643,6 +1643,15 @@ void VPInstructionWithType::execute(VPTransformState &State) {
   }
 }
 
+InstructionCost VPInstructionWithType::computeCost(ElementCount VF,
+                                                   VPCostContext &Ctx) const {
+  // TODO: Compute cost for VPInstructions without underlying values.
+  if (!getUnderlyingValue())
+    return 0;
+  return getCostForRecipeWithOpcode(getOpcode(), ElementCount::getFixed(1),
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fhahn wrote:

Yep, currently the only case we have underlying values is casts, added an assert.

https://github.com/llvm/llvm-project/pull/140623