[clang] [llvm] [clang-tools-extra] [VPlan] Introduce VPSingleDefRecipe. (PR #77023)

[via llvm-commits]

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@@ -12,6 +12,8 @@
 ///    VPBlockBase, together implementing a Hierarchical CFG;
 /// 2. Pure virtual VPRecipeBase serving as the base class for recipes contained
 ///    within VPBasicBlocks;
+/// 3. Pure virtual VPSingleDefRecipe serving as a base class for recipes that
+///    also inherit from VPValue.
 /// 3. VPInstruction, a concrete Recipe and VPUser modeling a single planned
 ///    instruction;
 /// 4. The VPlan class holding a candidate for vectorization;
----------------
ayalz wrote:

also renumber 5 to 6 next, but this unfortunately cannot be commented directly - falling more than 3 lines away from patched code:
```suggestion
/// 4. VPInstruction, a concrete Recipe and VPUser modeling a single planned
///    instruction;
/// 5. The VPlan class holding a candidate for vectorization;
```


https://github.com/llvm/llvm-project/pull/77023