[llvm] [VPlan] Perform optimizeMaskToEVL in terms of pattern matching (PR #155394)

[Ramkumar Ramachandra via llvm-commits]

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@@ -2272,90 +2272,98 @@ void VPlanTransforms::addActiveLaneMask(
   HeaderMask->eraseFromParent();
 }
 
+template <typename Op0_t, typename Op1_t> struct RemoveMask_match {
+  Op0_t In;
+  Op1_t &Out;
+
+  RemoveMask_match(const Op0_t &In, Op1_t &Out) : In(In), Out(Out) {}
+
+  template <typename OpTy> bool match(OpTy *V) const {
+    if (m_Specific(In).match(V)) {
+      Out = nullptr;
+      return true;
+    }
+    if (m_LogicalAnd(m_Specific(In), m_VPValue(Out)).match(V))
+      return true;
+    return false;
+  }
+};
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artagnon wrote:

Seems like a clever innovation!

https://github.com/llvm/llvm-project/pull/155394