[Mlir-commits] [mlir] [mlir] Extract forall_to_for logic into reusable function and add pass (PR #89636)

[Jorn Tuyls]

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@@ -0,0 +1,92 @@
+//===- ForallToFor.cpp - scf.forall to scf.for loop conversion ------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Transforms SCF.ForallOp's into SCF.ForOp's.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/SCF/Transforms/Passes.h"
+
+#include "mlir/Dialect/SCF/IR/SCF.h"
+#include "mlir/Dialect/SCF/Transforms/Transforms.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+
+namespace mlir {
+#define GEN_PASS_DEF_SCFFORALLTOFORLOOP
+#include "mlir/Dialect/SCF/Transforms/Passes.h.inc"
+} // namespace mlir
+
+using namespace llvm;
+using namespace mlir;
+using scf::ForallOp;
+using scf::ForOp;
+
+LogicalResult
+mlir::scf::forallToForLoop(RewriterBase &rewriter, scf::ForallOp forallOp,
+                           SmallVector<Operation *> *results = nullptr) {
+  rewriter.setInsertionPoint(forallOp);
+
+  if (!forallOp.getOutputs().empty()) {
+    return forallOp.emitOpError()
+           << "unsupported shared outputs (didn't bufferize?)";
+  }
+
+  SmallVector<OpFoldResult> lbs = forallOp.getMixedLowerBound();
+  SmallVector<OpFoldResult> ubs = forallOp.getMixedUpperBound();
+  SmallVector<OpFoldResult> steps = forallOp.getMixedStep();
+
+  auto loc = forallOp.getLoc();
+  SmallVector<Value> ivs;
+  for (auto &&[lb, ub, step] : llvm::zip(lbs, ubs, steps)) {
+    Value lbValue = getValueOrCreateConstantIndexOp(rewriter, loc, lb);
+    Value ubValue = getValueOrCreateConstantIndexOp(rewriter, loc, ub);
+    Value stepValue = getValueOrCreateConstantIndexOp(rewriter, loc, step);
+    auto loop =
+        rewriter.create<ForOp>(loc, lbValue, ubValue, stepValue, ValueRange(),
+                               [](OpBuilder &, Location, Value, ValueRange) {});
+    if (results)
+      results->push_back(loop);
+    ivs.push_back(loop.getInductionVar());
+    rewriter.setInsertionPointToStart(loop.getBody());
+    rewriter.create<scf::YieldOp>(loc);
+    rewriter.setInsertionPointToStart(loop.getBody());
+  }
+  rewriter.eraseOp(forallOp.getBody()->getTerminator());
+  rewriter.inlineBlockBefore(forallOp.getBody(), &*rewriter.getInsertionPoint(),
+                             ivs);
+  rewriter.eraseOp(forallOp);
+  return success();
+}
+
+namespace {
+struct ForallToForLoopLoweringPattern : public OpRewritePattern<ForallOp> {
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jtuyls wrote:

Done

https://github.com/llvm/llvm-project/pull/89636