[llvm] [VPlan] Impl VPlan-based pattern match for ExtendedRed and MulAccRed (PR #113903)

[Florian Hahn via llvm-commits]

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@@ -14,6 +14,7 @@
 #define LLVM_TRANSFORMS_VECTORIZE_VPLANTRANSFORMS_H
 
 #include "VPlan.h"
+#include "VPlanHelpers.h"
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fhahn wrote:

can forward declare `VPCostContext` instead of including `VPlanHelpers.h`?

https://github.com/llvm/llvm-project/pull/113903