[Mlir-commits] [mlir] [mlir][vector] Flatten transfer - support multi-dim scalar element (PR #185417)

[Andrzej Warzyński]

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@@ -835,11 +835,19 @@ class FlattenContiguousRowMajorTransferReadPattern
       return failure();
     }
 
+    // Determine vector dimensions to collapse.
+    // Ignore a leading sequence of adjacent unit dimensions in the vector.
+    ArrayRef<int64_t> collapsedVectorShape =
+        vectorType.getShape().drop_while([](auto v) { return v == 1; });
+    size_t collapsedVecRank = collapsedVectorShape.size();
+    // In case of a multi-dimensional scalar vector, restrict the shape collapse
+    // to a 1D vector.
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banach-space wrote:

[ultra nit] To me, scalar != vector, so this comment feels a bit odd (though I totally know what you mean and also find it hard to phrase it better). In any case, I have two suggestions:

* "Collapse multi-dimensional unit vectors (e.g., <1x1x1x1xf32>) to a 1D single-element vector."
* "If a vector has only one element in every dimension, flatten it to a 1D vector of length 1."

https://github.com/llvm/llvm-project/pull/185417