Files
clang-p2996/mlir/lib/Transforms/SimplifyAffineStructures.cpp
River Riddle 10237de8eb Refactor the affine analysis by moving some functionality to IR and some to AffineOps. This is important for allowing the affine dialect to define canonicalizations directly on the operations instead of relying on transformation passes, e.g. ComposeAffineMaps. A summary of the refactoring:
* AffineStructures has moved to IR.

* simplifyAffineExpr/simplifyAffineMap/getFlattenedAffineExpr have moved to IR.

* makeComposedAffineApply/fullyComposeAffineMapAndOperands have moved to AffineOps.

* ComposeAffineMaps is replaced by AffineApplyOp::canonicalize and deleted.

PiperOrigin-RevId: 232586468
2019-03-29 16:15:41 -07:00

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3.0 KiB
C++

//===- SimplifyAffineStructures.cpp - ---------------------------*- C++ -*-===//
//
// Copyright 2019 The MLIR Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// =============================================================================
//
// This file implements a pass to simplify affine structures.
//
//===----------------------------------------------------------------------===//
#include "mlir/IR/AffineStructures.h"
#include "mlir/IR/Function.h"
#include "mlir/IR/Instruction.h"
#include "mlir/IR/IntegerSet.h"
#include "mlir/Pass.h"
#include "mlir/Transforms/Passes.h"
#define DEBUG_TYPE "simplify-affine-structure"
using namespace mlir;
namespace {
/// Simplifies all affine expressions appearing in the operation instructions of
/// the Function. This is mainly to test the simplifyAffineExpr method.
/// TODO(someone): This should just be defined as a canonicalization pattern
/// on AffineMap and driven from the existing canonicalization pass.
struct SimplifyAffineStructures : public FunctionPass {
explicit SimplifyAffineStructures()
: FunctionPass(&SimplifyAffineStructures::passID) {}
PassResult runOnFunction(Function *f) override;
static char passID;
};
} // end anonymous namespace
char SimplifyAffineStructures::passID = 0;
FunctionPass *mlir::createSimplifyAffineStructuresPass() {
return new SimplifyAffineStructures();
}
/// Performs basic integer set simplifications. Checks if it's empty, and
/// replaces it with the canonical empty set if it is.
static IntegerSet simplifyIntegerSet(IntegerSet set) {
FlatAffineConstraints fac(set);
if (fac.isEmpty())
return IntegerSet::getEmptySet(set.getNumDims(), set.getNumSymbols(),
set.getContext());
return set;
}
PassResult SimplifyAffineStructures::runOnFunction(Function *f) {
f->walk([&](Instruction *opInst) {
for (auto attr : opInst->getAttrs()) {
if (auto mapAttr = attr.second.dyn_cast<AffineMapAttr>()) {
MutableAffineMap mMap(mapAttr.getValue());
mMap.simplify();
auto map = mMap.getAffineMap();
opInst->setAttr(attr.first, AffineMapAttr::get(map));
} else if (auto setAttr = attr.second.dyn_cast<IntegerSetAttr>()) {
auto simplified = simplifyIntegerSet(setAttr.getValue());
opInst->setAttr(attr.first, IntegerSetAttr::get(simplified));
}
}
});
return success();
}
static PassRegistration<SimplifyAffineStructures>
pass("simplify-affine-structures", "Simplify affine expressions");