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//===- ReduceInstructions.cpp - Specialized Delta Pass ---------------------===//
//
// 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 a function which calls the Generic Delta pass in order
// to reduce uninteresting Instructions from defined functions.
//
//===----------------------------------------------------------------------===//
#include "ReduceInstructions.h"
#include "Utils.h"
using namespace llvm;
/// Filter out cases where deleting the instruction will likely cause the
/// user/def of the instruction to fail the verifier.
//
// TODO: Technically the verifier only enforces preallocated token usage and
// there is a none token.
static bool shouldAlwaysKeep(const Instruction &I) {
return I.isEHPad() || I.getType()->isTokenTy() || I.isSwiftError();
}
/// Removes out-of-chunk arguments from functions, and modifies their calls
/// accordingly. It also removes allocations of out-of-chunk arguments.
void llvm::reduceInstructionsDeltaPass(Oracle &O, ReducerWorkItem &WorkItem) {
Module &Program = WorkItem.getModule();
for (auto &F : Program) {
for (auto &BB : F) {
// Removing the terminator would make the block invalid. Only iterate over
// instructions before the terminator.
for (auto &Inst :
make_early_inc_range(make_range(BB.begin(), std::prev(BB.end())))) {
if (!shouldAlwaysKeep(Inst) && !O.shouldKeep()) {
Inst.replaceAllUsesWith(getDefaultValue(Inst.getType()));
Inst.eraseFromParent();
}
}
}
}
}
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