[Mlir-commits] [mlir] [mlir][Vector] Promote buffers accessed via dynamic subviews and memref.copy (PR #217793)

[Jianhui Li]

================
@@ -84,43 +92,156 @@ getPromotableSubViewOffsets(memref::SubViewOp subView) {
        llvm::zip_equal(subView.getMixedSizes(), resType.getShape())) {
     std::optional<int64_t> s = getConstantIntValue(size);
     if (!s || *s != dim)
-      return std::nullopt;
+      return false;
+  }
+  return true;
+}
+
+/// Returns the static offsets of `subView` within the parent vector for
+/// `vector.extract_strided_slice` and `vector.insert_strided_slice`.
+static SmallVector<int64_t> getStaticSubViewOffsets(memref::SubViewOp subView) {
+  SmallVector<int64_t> offsets;
+  for (OpFoldResult offset : subView.getMixedOffsets()) {
+    std::optional<int64_t> value = getConstantIntValue(offset);
+    assert(value && "expected a static offset");
+    offsets.push_back(*value);
   }
   return offsets;
 }
+
+/// Returns whether `subView` can be promoted as an alias of the whole parent
+/// vector. Static shapes are handled by `isAliasableStaticShapeSubView`
+/// instead.
+static bool isAliasableDynamicShapeSubView(memref::SubViewOp subView) {
+  // The parent must be statically shaped so the slot has a fixed-shape vector
+  // type; only the subview's sizes may be dynamic.
+  auto srcType = dyn_cast<MemRefType>(subView.getSource().getType());
+  auto resType = dyn_cast<MemRefType>(subView.getResult().getType());
+  if (!srcType || !resType || !srcType.hasStaticShape())
+    return false;
+
+  // At least one dynamic result dimension; a fully static sub-slice is handled
+  // by `isAliasableStaticShapeSubView` instead.
+  if (resType.hasStaticShape())
----------------
Jianhui-Li wrote:

There are different checks:  L120 is to check subview's source memref must be static. Here it checks its result must not be static. 

https://github.com/llvm/llvm-project/pull/217793