a9f62244f2
Move the implementation of `ReconcileUnrealizedCasts` to `DialectConversion.cpp`, so that it can be called from there in a future commit. This commit is in preparation of decoupling argument/source/target materializations from the dialect conversion framework. The existing logic around unresolved materializations that predicts IR changes to decide if a cast op can be folded/erased will become obsolete, as `ReconcileUnrealizedCasts` will perform these kind of foldings on fully materialized IR. --------- Co-authored-by: Markus Böck <markus.boeck02@gmail.com>
55 lines
1.8 KiB
C++
55 lines
1.8 KiB
C++
//===- ReconcileUnrealizedCasts.cpp - Eliminate noop unrealized casts -----===//
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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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#include "mlir/Conversion/ReconcileUnrealizedCasts/ReconcileUnrealizedCasts.h"
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#include "mlir/IR/BuiltinOps.h"
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#include "mlir/Pass/Pass.h"
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#include "mlir/Transforms/DialectConversion.h"
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namespace mlir {
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#define GEN_PASS_DEF_RECONCILEUNREALIZEDCASTS
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#include "mlir/Conversion/Passes.h.inc"
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} // namespace mlir
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using namespace mlir;
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namespace {
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/// Pass to simplify and eliminate unrealized conversion casts.
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///
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/// This pass processes unrealized_conversion_cast ops in a worklist-driven
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/// fashion. For each matched cast op, if the chain of input casts eventually
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/// reaches a cast op where the input types match the output types of the
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/// matched op, replace the matched op with the inputs.
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///
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/// Example:
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/// %1 = unrealized_conversion_cast %0 : !A to !B
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/// %2 = unrealized_conversion_cast %1 : !B to !C
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/// %3 = unrealized_conversion_cast %2 : !C to !A
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///
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/// In the above example, %0 can be used instead of %3 and all cast ops are
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/// folded away.
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struct ReconcileUnrealizedCasts
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: public impl::ReconcileUnrealizedCastsBase<ReconcileUnrealizedCasts> {
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ReconcileUnrealizedCasts() = default;
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void runOnOperation() override {
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SmallVector<UnrealizedConversionCastOp> ops;
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getOperation()->walk(
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[&](UnrealizedConversionCastOp castOp) { ops.push_back(castOp); });
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reconcileUnrealizedCasts(ops);
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}
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};
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} // namespace
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std::unique_ptr<Pass> mlir::createReconcileUnrealizedCastsPass() {
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return std::make_unique<ReconcileUnrealizedCasts>();
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}
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