[Mlir-commits] [mlir] [mlir][vector] Migrate drop-lead-unit-dim to shape_cast (PR #196206)

[Erick Ochoa Lopez]

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@@ -45,14 +50,81 @@ static VectorType trimLeadingOneDims(VectorType oldType) {
   return VectorType::get(newShape, oldType.getElementType(), newScalableDims);
 }
 
-/// Return a smallVector of size `rank` containing all zeros.
-static SmallVector<int64_t> splatZero(int64_t rank) {
-  return SmallVector<int64_t>(rank, 0);
+/// Returns `value` if it already has `newType`, otherwise inserts a
+/// vector.shape_cast to `newType`.
+static Value shapeCastVector(OpBuilder &b, Location loc, Value value,
+                             VectorType newType) {
+  if (value.getType() == newType)
+    return value;
+  return vector::ShapeCastOp::create(b, loc, newType, value);
+}
+
+static bool hasNonScalableUnitLeadingDims(VectorType type, int64_t dropCount) {
+  if (dropCount < 0 || dropCount > type.getRank())
+    return false;
+  ArrayRef<int64_t> leadingShape = type.getShape().take_front(dropCount);
+  ArrayRef<bool> leadingScalable = type.getScalableDims().take_front(dropCount);
+  return llvm::all_of(leadingShape, [](int64_t dim) { return dim == 1; }) &&
+         llvm::none_of(leadingScalable, [](bool scalable) { return scalable; });
+}
+
+static bool isNonScalableUnitDim(VectorType type, int64_t dim) {
+  return dim >= 0 && dim < type.getRank() && type.getShape()[dim] == 1 &&
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amd-eochoalo wrote:

Can the bounds check be an assert here? 

https://github.com/llvm/llvm-project/pull/196206