[llvm] [VPlan] Add VPBundleRecipe, replacing extended reduction recipes. (PR #144281)

[Sam Tebbs via llvm-commits]

================
@@ -2922,6 +2710,123 @@ class VPBranchOnMaskRecipe : public VPRecipeBase {
   }
 };
 
+/// A recipe to combine multiple recipes into a 'bundle' recipe, which should be
+/// considered as single entity for cost-modeling and transforms. The recipe
+/// needs to be 'unbundled', i.e. replaced by its individual recipes before
+/// execute.
+class VPBundleRecipe : public VPSingleDefRecipe {
+  enum class BundleTypes {
+    ExtendedReduction,
+    MulAccumulateReduction,
+  };
+
+  /// Recipes bundled together in this VPBundleRecipe.
+  SmallVector<VPSingleDefRecipe *> BundledOps;
+
+  /// Temporary VPValues used for external operands of the bundle, i.e. operands
+  /// not defined by recipes in the bundle.
+  SmallVector<VPValue *> TmpValues;
+
+  /// Type of the bundle.
+  BundleTypes BundleType;
+
+  VPBundleRecipe(BundleTypes BundleType, ArrayRef<VPSingleDefRecipe *> ToBundle)
+      : VPSingleDefRecipe(VPDef::VPBundleSC, {}, {}), BundledOps(ToBundle),
+        BundleType(BundleType) {
+    // Bundle up the operand recipes.
+    SmallPtrSet<VPUser *, 4> BundledUsers;
+    for (auto *R : ToBundle)
+      BundledUsers.insert(R);
+
+    // Recipes in the bundle, expect the last one, must only be used inside the
----------------
SamTebbs33 wrote:

expect -> except

https://github.com/llvm/llvm-project/pull/144281