[llvm] [LV] Widen truncated induction updates, not just truncated phis (PR #220730)

[Luke Lau via llvm-commits]

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@@ -761,6 +761,21 @@ enum EpilogueLowering {
 
 enum class AliasMaskingStatus { NotDecided, Disabled, Enabled };
 
+/// Information about a truncation of an induction phi or its update that can
+/// be represented as an induction in the truncated type.
+struct OptimizableIVTruncateInfo {
+  /// The original induction phi.
+  PHINode *Phi = nullptr;
+  /// The induction update being truncated, or nullptr if the phi is truncated
+  /// directly.
+  Instruction *Update = nullptr;
+
+  OptimizableIVTruncateInfo() = default;
+
+  OptimizableIVTruncateInfo(PHINode *Phi, Instruction *Update)
+      : Phi(Phi), Update(Update) {}
+};
+
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lukel97 wrote:

Do we really need a struct that just holds two pointers?

https://github.com/llvm/llvm-project/pull/220730