Files
clang-p2996/mlir/lib/Dialect/SCF/Transforms/LoopRangeFolding.cpp
Michele Scuttari 67d0d7ac0a [MLIR] Update pass declarations to new autogenerated files
The patch introduces the required changes to update the pass declarations and definitions to use the new autogenerated files and allow dropping the old infrastructure.

Reviewed By: mehdi_amini, rriddle

Differential Review: https://reviews.llvm.org/D132838
2022-08-31 12:28:45 +02:00

92 lines
2.7 KiB
C++

//===- LoopRangeFolding.cpp - Code to perform loop range folding-----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements loop range folding.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/SCF/Transforms/Passes.h"
#include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
#include "mlir/Dialect/SCF/IR/SCF.h"
#include "mlir/Dialect/SCF/Transforms/Transforms.h"
#include "mlir/Dialect/SCF/Utils/Utils.h"
#include "mlir/IR/BlockAndValueMapping.h"
namespace mlir {
#define GEN_PASS_DEF_SCFFORLOOPRANGEFOLDING
#include "mlir/Dialect/SCF/Transforms/Passes.h.inc"
} // namespace mlir
using namespace mlir;
using namespace mlir::scf;
namespace {
struct ForLoopRangeFolding
: public impl::SCFForLoopRangeFoldingBase<ForLoopRangeFolding> {
void runOnOperation() override;
};
} // namespace
void ForLoopRangeFolding::runOnOperation() {
getOperation()->walk([&](ForOp op) {
Value indVar = op.getInductionVar();
auto canBeFolded = [&](Value value) {
return op.isDefinedOutsideOfLoop(value) || value == indVar;
};
// Fold until a fixed point is reached
while (true) {
// If the induction variable is used more than once, we can't fold its
// arith ops into the loop range
if (!indVar.hasOneUse())
break;
Operation *user = *indVar.getUsers().begin();
if (!isa<arith::AddIOp, arith::MulIOp>(user))
break;
if (!llvm::all_of(user->getOperands(), canBeFolded))
break;
OpBuilder b(op);
BlockAndValueMapping lbMap;
lbMap.map(indVar, op.getLowerBound());
BlockAndValueMapping ubMap;
ubMap.map(indVar, op.getUpperBound());
BlockAndValueMapping stepMap;
stepMap.map(indVar, op.getStep());
if (isa<arith::AddIOp>(user)) {
Operation *lbFold = b.clone(*user, lbMap);
Operation *ubFold = b.clone(*user, ubMap);
op.setLowerBound(lbFold->getResult(0));
op.setUpperBound(ubFold->getResult(0));
} else if (isa<arith::MulIOp>(user)) {
Operation *ubFold = b.clone(*user, ubMap);
Operation *stepFold = b.clone(*user, stepMap);
op.setUpperBound(ubFold->getResult(0));
op.setStep(stepFold->getResult(0));
}
ValueRange wrapIndvar(indVar);
user->replaceAllUsesWith(wrapIndvar);
user->erase();
}
});
}
std::unique_ptr<Pass> mlir::createForLoopRangeFoldingPass() {
return std::make_unique<ForLoopRangeFolding>();
}