mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-26 07:29:55 +00:00
Sooooo many of these had incorrect or strange main module includes. I have manually inspected all of these, and fixed the main module include to be the nearest plausible thing I could find. If you own or care about any of these source files, I encourage you to take some time and check that these edits were sensible. I can't have broken anything (I strictly added headers, and reordered them, never removed), but they may not be the headers you'd really like to identify as containing the API being implemented. Many forward declarations and missing includes were added to a header files to allow them to parse cleanly when included first. The main module rule does in fact have its merits. =] git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
135 lines
4.3 KiB
C++
135 lines
4.3 KiB
C++
//===- DCE.cpp - Code to perform dead code elimination --------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements dead inst elimination and dead code elimination.
|
|
//
|
|
// Dead Inst Elimination performs a single pass over the function removing
|
|
// instructions that are obviously dead. Dead Code Elimination is similar, but
|
|
// it rechecks instructions that were used by removed instructions to see if
|
|
// they are newly dead.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#define DEBUG_TYPE "dce"
|
|
#include "llvm/Transforms/Scalar.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/Instruction.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Support/InstIterator.h"
|
|
#include "llvm/Target/TargetLibraryInfo.h"
|
|
#include "llvm/Transforms/Utils/Local.h"
|
|
using namespace llvm;
|
|
|
|
STATISTIC(DIEEliminated, "Number of insts removed by DIE pass");
|
|
STATISTIC(DCEEliminated, "Number of insts removed");
|
|
|
|
namespace {
|
|
//===--------------------------------------------------------------------===//
|
|
// DeadInstElimination pass implementation
|
|
//
|
|
struct DeadInstElimination : public BasicBlockPass {
|
|
static char ID; // Pass identification, replacement for typeid
|
|
DeadInstElimination() : BasicBlockPass(ID) {
|
|
initializeDeadInstEliminationPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
virtual bool runOnBasicBlock(BasicBlock &BB) {
|
|
TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
|
|
bool Changed = false;
|
|
for (BasicBlock::iterator DI = BB.begin(); DI != BB.end(); ) {
|
|
Instruction *Inst = DI++;
|
|
if (isInstructionTriviallyDead(Inst, TLI)) {
|
|
Inst->eraseFromParent();
|
|
Changed = true;
|
|
++DIEEliminated;
|
|
}
|
|
}
|
|
return Changed;
|
|
}
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesCFG();
|
|
}
|
|
};
|
|
}
|
|
|
|
char DeadInstElimination::ID = 0;
|
|
INITIALIZE_PASS(DeadInstElimination, "die",
|
|
"Dead Instruction Elimination", false, false)
|
|
|
|
Pass *llvm::createDeadInstEliminationPass() {
|
|
return new DeadInstElimination();
|
|
}
|
|
|
|
|
|
namespace {
|
|
//===--------------------------------------------------------------------===//
|
|
// DeadCodeElimination pass implementation
|
|
//
|
|
struct DCE : public FunctionPass {
|
|
static char ID; // Pass identification, replacement for typeid
|
|
DCE() : FunctionPass(ID) {
|
|
initializeDCEPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
virtual bool runOnFunction(Function &F);
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesCFG();
|
|
}
|
|
};
|
|
}
|
|
|
|
char DCE::ID = 0;
|
|
INITIALIZE_PASS(DCE, "dce", "Dead Code Elimination", false, false)
|
|
|
|
bool DCE::runOnFunction(Function &F) {
|
|
TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
|
|
|
|
// Start out with all of the instructions in the worklist...
|
|
std::vector<Instruction*> WorkList;
|
|
for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
|
|
WorkList.push_back(&*i);
|
|
|
|
// Loop over the worklist finding instructions that are dead. If they are
|
|
// dead make them drop all of their uses, making other instructions
|
|
// potentially dead, and work until the worklist is empty.
|
|
//
|
|
bool MadeChange = false;
|
|
while (!WorkList.empty()) {
|
|
Instruction *I = WorkList.back();
|
|
WorkList.pop_back();
|
|
|
|
if (isInstructionTriviallyDead(I, TLI)) { // If the instruction is dead.
|
|
// Loop over all of the values that the instruction uses, if there are
|
|
// instructions being used, add them to the worklist, because they might
|
|
// go dead after this one is removed.
|
|
//
|
|
for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI)
|
|
if (Instruction *Used = dyn_cast<Instruction>(*OI))
|
|
WorkList.push_back(Used);
|
|
|
|
// Remove the instruction.
|
|
I->eraseFromParent();
|
|
|
|
// Remove the instruction from the worklist if it still exists in it.
|
|
WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), I),
|
|
WorkList.end());
|
|
|
|
MadeChange = true;
|
|
++DCEEliminated;
|
|
}
|
|
}
|
|
return MadeChange;
|
|
}
|
|
|
|
FunctionPass *llvm::createDeadCodeEliminationPass() {
|
|
return new DCE();
|
|
}
|
|
|