[llvm] [LoadStoreVectorizer] Fill gaps in load/store chains to enable vectorization (PR #159388)

[Matt Arsenault via llvm-commits]

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@@ -817,6 +817,12 @@ class TargetTransformInfo {
   LLVM_ABI bool isLegalMaskedLoad(Type *DataType, Align Alignment,
                                   unsigned AddressSpace) const;
 
+  /// Return true if it is legal to widen loads beyond their current width,
+  /// assuming the result is still well-aligned. For example, converting a load
+  /// i32 to a load i64, or vectorizing three continuous load i32s into a load
+  /// <4 x i32>.
+  LLVM_ABI bool isLegalToWidenLoads() const;
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arsenm wrote:

No. I mean a hook without parameters corresponding to a specific load is close to useless. At minimum would need address space, alignment, type etc. 

https://github.com/llvm/llvm-project/pull/159388