[llvm] [VPlan] Introduce VPInstructionWithType, use instead of VPScalarCast(NFC) (PR #129706)

[via llvm-commits]

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@@ -1025,6 +1024,39 @@ void VPInstruction::print(raw_ostream &O, const Twine &Indent,
 }
 #endif
 
+Value *VPInstructionWithType::generate(VPTransformState &State) {
+  State.setDebugLocFrom(getDebugLoc());
+  assert(vputils::onlyFirstLaneUsed(this) &&
+         "Codegen only implemented for first lane.");
+  switch (getOpcode()) {
+  case Instruction::SExt:
+  case Instruction::ZExt:
+  case Instruction::Trunc: {
+    // Note: SExt/ZExt not used yet.
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ayalz wrote:

Then leave them as default until they are, to avoid dead code? Admittedly unrelated.

https://github.com/llvm/llvm-project/pull/129706