[Mlir-commits] [mlir] [mlir] Do not bufferize parallel_insert_slice dest to read for full slices (PR #112761)

[Han-Chung Wang]

================
@@ -636,6 +637,34 @@ struct InsertOpInterface
   }
 };
 
+template <typename InsertOpTy>
+static bool insertSliceOpRequiresRead(InsertOpTy insertSliceOp,
+                                      OpOperand &opOperand) {
+  RankedTensorType destType = insertSliceOp.getDestType();
+
+  // The source is always read.
+  if (opOperand == insertSliceOp.getSourceMutable())
+    return true;
+
+  // For the destination, it depends...
+  assert(opOperand == insertSliceOp.getDestMutable() && "expected dest");
+
+  // Dest is not read if it is entirely overwritten. E.g.:
+  // tensor.insert_slice %a into %t[0][10][1] : ... into tensor<10xf32>
+  bool allOffsetsZero =
+      llvm::all_of(insertSliceOp.getMixedOffsets(),
+                   [](OpFoldResult ofr) { return isConstantIntValue(ofr, 0); });
+  bool sizesMatchDestSizes = llvm::all_of(
+      llvm::enumerate(insertSliceOp.getMixedSizes()), [&](const auto &it) {
+        return getConstantIntValue(it.value()) ==
+               destType.getDimSize(it.index());
+      });
+  bool allStridesOne =
+      llvm::all_of(insertSliceOp.getMixedStrides(),
+                   [](OpFoldResult ofr) { return isConstantIntValue(ofr, 1); });
----------------
hanhanW wrote:

We can consider adding a new method to `StaticValueUtils.h`, which takes an ArrayRef and check if the values are all `value` or not.

```cpp
 bool isConstantIntValue(ArrayRef<OpFoldResult ofr>, int64_t value); 
// or name it to isConstantIntValueArray
```

https://github.com/llvm/llvm-project/blob/8c62bf54df76e37d0978f4901c6be6554e978b53/mlir/include/mlir/Dialect/Utils/StaticValueUtils.h#L93-L94

https://github.com/llvm/llvm-project/pull/112761