[llvm] [VPlan] Strip erroneous poisonGuaranteesUB (PR #189374)

[Ramkumar Ramachandra via llvm-commits]

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@@ -83,61 +83,6 @@ bool vputils::isHeaderMask(const VPValue *V, const VPlan &Plan) {
          B == Plan.getBackedgeTakenCount();
 }
 
-/// Returns true if \p R propagates poison from any operand to its result.
-static bool propagatesPoisonFromRecipeOp(const VPRecipeBase *R) {
-  return TypeSwitch<const VPRecipeBase *, bool>(R)
-      .Case<VPWidenGEPRecipe, VPWidenCastRecipe>(
-          [](const VPRecipeBase *) { return true; })
-      .Case([](const VPReplicateRecipe *Rep) {
-        // GEP and casts propagate poison from all operands.
-        unsigned Opcode = Rep->getOpcode();
-        return Opcode == Instruction::GetElementPtr ||
-               Instruction::isCast(Opcode);
-      })
-      .Default([](const VPRecipeBase *) { return false; });
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artagnon wrote:

@fhahn Can you comment on this patch? I discovered the problem by changing this to match all GEPs via m_GetElementPtr, which causes cost-model crashes.

https://github.com/llvm/llvm-project/pull/189374