add shared loop creation helpers

add shared checked arithmetic helpers
refactor pim passes into Pim/Transforms
more robust memory coalescing pass

src/PIM/Common/IR/LoopUtils.cpp

@@ -0,0 +1,96 @@
+#include "mlir/Dialect/SCF/IR/SCF.h"
+
+#include "llvm/Support/MathExtras.h"
+
+#include <optional>
+
+#include "ConstantUtils.hpp"
+#include "LoopUtils.hpp"
+
+using namespace mlir;
+
+namespace onnx_mlir {
+
+namespace {
+
+static std::optional<int64_t> getStaticTripCount(Value lowerBound, Value upperBound, Value step) {
+  auto lower = matchConstantIndexValue(lowerBound);
+  auto upper = matchConstantIndexValue(upperBound);
+  auto stepValue = matchConstantIndexValue(step);
+  if (!lower || !upper || !stepValue)
+    return std::nullopt;
+  if (*stepValue <= 0)
+    return std::nullopt;
+  if (*upper <= *lower)
+    return int64_t {0};
+  return llvm::divideCeil(*upper - *lower, *stepValue);
+}
+
+} // namespace
+
+static LogicalResult validateNormalizedLoopYields(Location loc, ValueRange initArgs, ArrayRef<Value> yieldedValues) {
+  if (yieldedValues.size() == initArgs.size())
+    return success();
+
+  emitError(loc) << "normalized loop body yielded " << yieldedValues.size() << " values for " << initArgs.size()
+                 << " iter args";
+  return failure();
+}
+
+FailureOr<NormalizedLoopResult> buildNormalizedScfFor(OpBuilder& builder,
+                                                      Location loc,
+                                                      Value lowerBound,
+                                                      Value upperBound,
+                                                      Value step,
+                                                      ValueRange initArgs,
+                                                      NormalizedLoopBodyBuilder bodyBuilder) {
+  NormalizedLoopResult result;
+
+  if (auto stepValue = matchConstantIndexValue(step); stepValue && *stepValue <= 0) {
+    emitError(loc) << "normalized scf.for requires a positive step, got " << *stepValue;
+    return failure();
+  }
+
+  if (auto tripCount = getStaticTripCount(lowerBound, upperBound, step)) {
+    if (*tripCount == 0) {
+      llvm::append_range(result.results, initArgs);
+      return result;
+    }
+
+    if (*tripCount == 1) {
+      result.inductionVar = lowerBound;
+      if (failed(bodyBuilder(builder, loc, lowerBound, initArgs, result.results)))
+        return failure();
+      if (failed(validateNormalizedLoopYields(loc, initArgs, result.results)))
+        return failure();
+      return result;
+    }
+  }
+
+  result.loop = scf::ForOp::create(builder, loc, lowerBound, upperBound, step, initArgs);
+  result.inductionVar = result.loop.getInductionVar();
+
+  {
+    OpBuilder::InsertionGuard guard(builder);
+    Block* body = result.loop.getBody();
+    if (!body->empty())
+      if (auto yieldOp = dyn_cast<scf::YieldOp>(body->back()))
+        yieldOp->erase();
+    builder.setInsertionPointToEnd(body);
+    ValueRange iterArgs = result.loop.getRegionIterArgs();
+    if (failed(bodyBuilder(builder, loc, result.inductionVar, iterArgs, result.results))) {
+      result.loop.erase();
+      return failure();
+    }
+    if (failed(validateNormalizedLoopYields(loc, initArgs, result.results))) {
+      result.loop.erase();
+      return failure();
+    }
+    scf::YieldOp::create(builder, loc, result.results);
+  }
+  builder.setInsertionPointAfter(result.loop);
+  result.results.assign(result.loop.getResults().begin(), result.loop.getResults().end());
+  return result;
+}
+
+} // namespace onnx_mlir

src/PIM/Common/IR/LoopUtils.hpp

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "mlir/Dialect/SCF/IR/SCF.h"
+#include "mlir/IR/Builders.h"
+
+#include "llvm/ADT/STLFunctionalExtras.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace onnx_mlir {
+
+struct NormalizedLoopResult {
+  mlir::Value inductionVar;
+  llvm::SmallVector<mlir::Value, 4> results;
+  mlir::scf::ForOp loop;
+
+  bool wasInlined() const { return !loop; }
+};
+
+using NormalizedLoopBodyBuilder = llvm::function_ref<mlir::LogicalResult(
+  mlir::OpBuilder&, mlir::Location, mlir::Value, mlir::ValueRange, llvm::SmallVectorImpl<mlir::Value>&)>;
+
+mlir::FailureOr<NormalizedLoopResult> buildNormalizedScfFor(mlir::OpBuilder& builder,
+                                                            mlir::Location loc,
+                                                            mlir::Value lowerBound,
+                                                            mlir::Value upperBound,
+                                                            mlir::Value step,
+                                                            mlir::ValueRange initArgs,
+                                                            NormalizedLoopBodyBuilder bodyBuilder);
+
+} // namespace onnx_mlir