[Mlir-commits] [mlir] [mlir][vector] Add mask elimination transform (PR #99314)

[Andrzej Warzyński]

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@@ -0,0 +1,114 @@
+//===- VectorMaskElimination.cpp - Eliminate Vector Masks -----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/Utils/StaticValueUtils.h"
+#include "mlir/Dialect/Vector/IR/ScalableValueBoundsConstraintSet.h"
+#include "mlir/Dialect/Vector/Transforms/VectorRewritePatterns.h"
+#include "mlir/Dialect/Vector/Transforms/VectorTransforms.h"
+#include "mlir/Interfaces/FunctionInterfaces.h"
+
+using namespace mlir;
+using namespace mlir::vector;
+namespace {
+
+/// Attempts to resolve a (scalable) CreateMaskOp to an all-true constant mask.
+/// All-true masks can then be eliminated by simple folds.
+LogicalResult resolveAllTrueCreateMaskOp(IRRewriter &rewriter,
+                                         vector::CreateMaskOp createMaskOp,
+                                         VscaleRange vscaleRange) {
+  auto maskType = createMaskOp.getVectorType();
+  auto maskTypeDimScalableFlags = maskType.getScalableDims();
+  auto maskTypeDimSizes = maskType.getShape();
+
+  struct UnknownMaskDim {
+    size_t position;
+    Value dimSize;
+  };
+
+  // Check for any dims that could be (partially) false before doing the more
+  // expensive value bounds computations.
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banach-space wrote:

Same comment as in VectorOps.cpp. Also, please add a note that this will collect dims for further analysis.

https://github.com/llvm/llvm-project/pull/99314