[llvm] [VPlan] Add VPPhiAccessors to provide interface for phi recipes (NFC) (PR #138472)

[Ramkumar Ramachandra via llvm-commits]

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@@ -1224,6 +1224,42 @@ class VPPhiAccessors {
     return getAsRecipe()->getNumOperands();
   }
 
+  /// Returns an interator range over the incoming values.
+  VPUser::const_operand_range incoming_values() const {
+    return make_range(getAsRecipe()->op_begin(),
+                      getAsRecipe()->op_begin() + getNumIncoming());
+  }
+
+  using const_incoming_block_iterator =
+      mapped_iterator<detail::index_iterator,
+                      std::function<const VPBasicBlock *(size_t)>>;
+  using const_incoming_blocks_range =
+      iterator_range<const_incoming_block_iterator>;
+
+  const_incoming_block_iterator incoming_block_begin() const {
+    return const_incoming_block_iterator(
+        detail::index_iterator(0),
+        [this](size_t Idx) { return getIncomingBlock(Idx); });
+  }
+  const_incoming_block_iterator incoming_block_end() const {
+    return const_incoming_block_iterator(
+        detail::index_iterator(getNumIncoming()),
+        [this](size_t Idx) { return getIncomingBlock(Idx); });
+  }
+
+  /// Returns an iterator range over the incoming blocks.
+  const_incoming_blocks_range incoming_blocks() const {
+    return make_range(incoming_block_begin(), incoming_block_end());
+  }
+
+  /// Returns an iterator range over pairs of incoming values and corresponding
+  /// incoming blocks.
+  detail::zippy<llvm::detail::zip_first, VPUser::const_operand_range,
+                const_incoming_blocks_range>
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artagnon wrote:

I would be tempted to replace this with auto?

https://github.com/llvm/llvm-project/pull/138472