onnx-mlir/src/Conversion/ONNXToKrnl/Tensor/Pad.cpp

122 lines
4.3 KiB
C++

//===-----------------------Pad.cpp - Lowering Pad Op -------------------===//
//
// Copyright 2019 The IBM Research Authors.
//
// =============================================================================
//
// This file lowers the ONNX Pad Operator to Krnl dialect.
//
//===----------------------------------------------------------------------===//
#include "src/Conversion/ONNXToKrnl/ONNXToKrnlCommon.hpp"
using namespace mlir;
struct ONNXPadOpLowering : public ConversionPattern {
ONNXPadOpLowering(MLIRContext *ctx)
: ConversionPattern(mlir::ONNXPadOp::getOperationName(), 1, ctx) {}
LogicalResult matchAndRewrite(Operation *op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const final {
ONNXPadOp myOp = llvm::dyn_cast<ONNXPadOp>(op);
ONNXPadOpAdaptor operandAdaptor(operands);
auto tensorType = myOp.output().getType();
auto loc = op->getLoc();
// Only constant padding is supported now.
auto padMode = myOp.mode();
if (padMode != "constant")
return emitError(loc, "unsupported mode for Pad");
DenseElementsAttr constantValAttr =
myOp.getAttr("constant_value")
.dyn_cast_or_null<mlir::DenseElementsAttr>();
if (!constantValAttr)
return emitError(loc, "unsupported value");
DenseElementsAttr padsAttributes =
myOp.getAttr("pads").dyn_cast_or_null<mlir::DenseElementsAttr>();
if (!padsAttributes)
return emitError(loc, "Pad: unknown pads");
auto memRefType = convertToMemRefType(tensorType);
Value alloc;
bool insertDealloc = checkInsertDealloc(op);
if (hasAllConstantDimensions(memRefType))
alloc = insertAllocAndDealloc(memRefType, loc, rewriter, insertDealloc);
else
return emitError(loc, "unexpected output has non-Constant shape");
// Number of loops
auto memRefShape = memRefType.getShape();
int64_t rank = memRefShape.size();
// get the padding vector into a temporary smallvector
SmallVector<int64_t, 2> pads(rank * 2, -1);
auto padsIt = padsAttributes.getValues<IntegerAttr>().begin();
for (int i = 0; i < rank * 2; ++i)
pads[i] = (*padsIt++).cast<IntegerAttr>().getInt();
// get the padding value
auto valueAttr = (*constantValAttr.getValues<FloatAttr>().begin());
// Iterate over the loop nest using the output shape.
BuildKrnlLoop padLoops(rewriter, loc, rank);
padLoops.createDefineAndOptimizeOp();
for (int i = 0; i < rank; ++i)
padLoops.pushBounds(0, alloc, i);
padLoops.createIterateOp();
// Iterate over the loop nest using the input shape.
BuildKrnlLoop valueLoops(rewriter, loc, rank);
valueLoops.createDefineAndOptimizeOp();
for (int i = 0; i < rank; ++i)
valueLoops.pushBounds(0, operandAdaptor.data(), i);
valueLoops.createIterateOp();
// Copy the input data into the output.
rewriter.setInsertionPointToStart(valueLoops.getIterateBlock());
SmallVector<Value, 4> inLoopIVs;
for (int i = 0; i < rank; ++i)
inLoopIVs.emplace_back(valueLoops.getInductionVar(i));
SmallVector<Value, 4> outLoopIVs;
for (int i = 0; i < rank; ++i) {
// Calculate the index for the load and store.
if (pads[i] == 0) {
outLoopIVs.emplace_back(valueLoops.getInductionVar(i));
} else {
AffineMap indexWithOffsetMap =
AffineMap::get(1, 0, rewriter.getAffineDimExpr(0) + pads[i]);
Value outIV = rewriter.create<AffineApplyOp>(loc, indexWithOffsetMap,
ArrayRef<Value>{valueLoops.getInductionVar(i)});
outLoopIVs.emplace_back(outIV);
}
}
auto originValue =
rewriter.create<AffineLoadOp>(loc, operandAdaptor.data(), inLoopIVs);
rewriter.create<AffineStoreOp>(loc, originValue, alloc, outLoopIVs);
rewriter.setInsertionPointToStart(padLoops.getIterateBlock());
SmallVector<Value, 4> outLoopIVs1;
for (int i = 0; i < rank; ++i)
outLoopIVs1.emplace_back(padLoops.getInductionVar(i));
auto paddingValue = rewriter.create<ConstantOp>(loc, valueAttr);
rewriter.create<AffineStoreOp>(loc, paddingValue, alloc, outLoopIVs1);
// Replace the original op with the generated code.
rewriter.replaceOp(op, alloc);
return success();
}
};
void populateLoweringONNXPadOpPattern(
OwningRewritePatternList &patterns, MLIRContext *ctx) {
patterns.insert<ONNXPadOpLowering>(ctx);
}