aa93659c9f
This utility factors out the machinery required to add iterArgs and yield values to an scf.ForOp. Differential Revision: https://reviews.llvm.org/D80656
74 lines
3.0 KiB
C++
74 lines
3.0 KiB
C++
//===- LoopUtils.cpp ---- Misc utilities for loop transformation ----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements miscellaneous loop transformation routines.
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Dialect/SCF/Utils.h"
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#include "mlir/Dialect/SCF/SCF.h"
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#include "mlir/IR/BlockAndValueMapping.h"
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using namespace mlir;
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scf::ForOp mlir::cloneWithNewYields(OpBuilder &b, scf::ForOp loop,
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ValueRange newIterOperands,
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ValueRange newYieldedValues,
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bool replaceLoopResults) {
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assert(newIterOperands.size() == newYieldedValues.size() &&
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"newIterOperands must be of the same size as newYieldedValues");
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// Create a new loop before the existing one, with the extra operands.
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OpBuilder::InsertionGuard g(b);
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b.setInsertionPoint(loop);
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auto operands = llvm::to_vector<4>(loop.getIterOperands());
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operands.append(newIterOperands.begin(), newIterOperands.end());
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scf::ForOp newLoop =
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b.create<scf::ForOp>(loop.getLoc(), loop.lowerBound(), loop.upperBound(),
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loop.step(), operands);
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auto &loopBody = *loop.getBody();
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auto &newLoopBody = *newLoop.getBody();
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// Clone / erase the yield inside the original loop to both:
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// 1. augment its operands with the newYieldedValues.
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// 2. automatically apply the BlockAndValueMapping on its operand
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auto yield = cast<scf::YieldOp>(loopBody.getTerminator());
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b.setInsertionPoint(yield);
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auto yieldOperands = llvm::to_vector<4>(yield.getOperands());
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yieldOperands.append(newYieldedValues.begin(), newYieldedValues.end());
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auto newYield = b.create<scf::YieldOp>(yield.getLoc(), yieldOperands);
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// Clone the loop body with remaps.
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BlockAndValueMapping bvm;
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// a. remap the induction variable.
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bvm.map(loop.getInductionVar(), newLoop.getInductionVar());
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// b. remap the BB args.
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bvm.map(loopBody.getArguments(),
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newLoopBody.getArguments().take_front(loopBody.getNumArguments()));
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// c. remap the iter args.
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bvm.map(newIterOperands,
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newLoop.getRegionIterArgs().take_back(newIterOperands.size()));
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b.setInsertionPointToStart(&newLoopBody);
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// Skip the original yield terminator which does not have enough operands.
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for (auto &o : loopBody.without_terminator())
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b.clone(o, bvm);
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// Replace `loop`'s results if requested.
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if (replaceLoopResults) {
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for (auto it : llvm::zip(loop.getResults(), newLoop.getResults().take_front(
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loop.getNumResults())))
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std::get<0>(it).replaceAllUsesWith(std::get<1>(it));
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}
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// TODO: this is unsafe in the context of a PatternRewrite.
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newYield.erase();
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return newLoop;
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}
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