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

[via llvm-commits]

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@@ -10412,8 +10411,9 @@ preparePlanForEpilogueVectorLoop(VPlan &Plan, Loop *L,
       assert(all_of(IV->users(),
                     [](const VPUser *U) {
                       return isa<VPScalarIVStepsRecipe>(U) ||
-                             isa<VPScalarCastRecipe>(U) ||
                              isa<VPDerivedIVRecipe>(U) ||
+                             Instruction::isCast(
+                                 cast<VPInstruction>(U)->getOpcode()) ||
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ayalz wrote:

Worth wrapping in VPInstruction::isCast()?

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