[llvm] [VectorCombine] Align shrinkLoadForShuffles to register boundaries (PR #209775)

[Timur Golubovich via llvm-commits]

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@@ -6246,9 +6246,41 @@ bool VectorCombine::shrinkLoadForShuffles(Instruction &I) {
     return OutputRange;
   };
 
+  // Compute the new number of elements, aligning to vector register
+  // boundaries for fixed-width vectors to avoid non-power-of-2 remainders
+  // that legalize poorly.
+  auto GetAlignedNumElements = [&](unsigned MaxIdx,
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timurgol007 wrote:

@arsenm, addressed

https://github.com/llvm/llvm-project/pull/209775