[Mlir-commits] [mlir] [MLIR][LLVM] DI Expression Rewrite & Legalization (PR #77541)

[Billy Zhu]

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@@ -0,0 +1,74 @@
+//===- DIExpressionRewriter.cpp - Rewriter for DIExpression operators -----===//
+//
+// 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/LLVMIR/Transforms/DIExpressionRewriter.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+#include "llvm/Support/Debug.h"
+
+using namespace mlir;
+using namespace LLVM;
+
+#define DEBUG_TYPE "llvm-di-expression-simplifier"
+
+//===----------------------------------------------------------------------===//
+// DIExpressionRewriter
+//===----------------------------------------------------------------------===//
+
+void DIExpressionRewriter::addPattern(
+    std::unique_ptr<ExprRewritePattern> pattern) {
+  patterns.emplace_back(std::move(pattern));
+}
+
+DIExpressionAttr DIExpressionRewriter::simplify(DIExpressionAttr expr,
+                                                int64_t maxNumRewrites) const {
+  ArrayRef<OperatorT> operators = expr.getOperations();
+
+  // `inputs` contains the unprocessed postfix of operators.
+  // `result` contains the already finalized prefix of operators.
+  // Invariant: concat(result, inputs) is equivalent to `operators` after some
+  // application of the rewrite patterns.
+  // Using a deque for inputs so that we have efficient front insertion and
+  // removal. Random access is not necessary for patterns.
+  std::deque<OperatorT> inputs(operators.begin(), operators.end());
+  SmallVector<OperatorT> result;
+
+  int64_t numRewrites = 0;
+  while (!inputs.empty() &&
+         (maxNumRewrites < 0 || numRewrites < maxNumRewrites)) {
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zyx-billy wrote:

sounds good 👍 was a bit hesitant to wrap an int since the mlir rewriter was not, but I like this 😂 .

https://github.com/llvm/llvm-project/pull/77541