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b3730ed205
This patch adds a new reduction pass that tries to remove aliases. It runs early, as most of those likely can be removed up-front in practice. This substantially improves llvm-reduce for IR generated by the swift compiler, which can generate a lot of aliases which lead to lots of invalid reductions. Reviewed By: lebedev.ri Differential Revision: https://reviews.llvm.org/D90260
54 lines
1.8 KiB
C++
54 lines
1.8 KiB
C++
//===- ReduceAliases.cpp - Specialized Delta Pass -------------------------===//
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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 a function which calls the Generic Delta pass in order
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// to reduce aliases in the provided Module.
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//
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//===----------------------------------------------------------------------===//
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#include "ReduceAliases.h"
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#include "Delta.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/GlobalValue.h"
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using namespace llvm;
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/// Removes all aliases aren't inside any of the
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/// desired Chunks.
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static void extractAliasesFromModule(const std::vector<Chunk> &ChunksToKeep,
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Module *Program) {
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Oracle O(ChunksToKeep);
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for (auto &GA : make_early_inc_range(Program->aliases())) {
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if (!O.shouldKeep()) {
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GA.replaceAllUsesWith(GA.getAliasee());
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GA.eraseFromParent();
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}
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}
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}
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/// Counts the amount of aliases and prints their respective name & index.
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static int countAliases(Module *Program) {
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// TODO: Silence index with --quiet flag
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errs() << "----------------------------\n";
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errs() << "Aliases Index Reference:\n";
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int Count = 0;
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for (auto &GA : Program->aliases())
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errs() << "\t" << ++Count << ": " << GA.getName() << "\n";
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errs() << "----------------------------\n";
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return Count;
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}
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void llvm::reduceAliasesDeltaPass(TestRunner &Test) {
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errs() << "*** Reducing Aliases ...\n";
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int Functions = countAliases(Test.getProgram());
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runDeltaPass(Test, Functions, extractAliasesFromModule);
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errs() << "----------------------------\n";
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}
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