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dead code: fix for variables from loop headers

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This commit is contained in:
Mikhail Kocharmin
2024-04-05 16:03:18 +03:00
parent af194134ba
commit 5f4bb71dcf
1 changed files with 80 additions and 30 deletions
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110
sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp
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@@ -14,6 +14,40 @@ using std::set;
using std::remove_if;
#define PRINT_USELESS_STATEMENTS 1
#define DEBUG_IR 0
// detect wich registers are used at more than one block
// such registers should participate in live analysis to spread information about useful instructions
// such registers appears at loops
static void fillSharedRegs(const map<FuncInfo*, vector<SAPFOR::BasicBlock*>>& cfg, set<SAPFOR::Argument*>& shared_regs)
{
map<SAPFOR::Argument*, SAPFOR::BasicBlock*> used_at;
for (const auto& byFunc : cfg)
{
for (const auto& byBlock : byFunc.second)
{
for (const auto& byIrBlock : byBlock->getInstructions())
{
auto instr = byIrBlock->getInstruction();
set<SAPFOR::Argument*> used = { instr->getResult(), instr->getArg1(), instr->getArg2() };
for (auto arg : used)
{
if(arg && arg->getType() == SAPFOR::CFG_ARG_TYPE::REG)
{
auto it = used_at.find(arg);
if (it == used_at.end())
used_at[arg] = byBlock;
else if(it->second != byBlock)
shared_regs.insert(arg);
}
}
}
}
}
}
static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instruction* instr,
set<SAPFOR::Argument*>& use, set<SAPFOR::Argument*>& def,
@@ -91,7 +125,7 @@ static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instru
def.erase(e);
}
insertIfVar(args.begin(), args.end(), usedByThisBlock);
usedByThisBlock.insert(args.begin(), args.end());
}
if ((instr->getOperation() == SAPFOR::CFG_OP::F_CALL || instr->getOperation() == SAPFOR::CFG_OP::PARAM) && fName == "")
@@ -130,8 +164,8 @@ static void buildUseDef(SAPFOR::BasicBlock* block, set<SAPFOR::Argument*>& use,
useful[i] = u;
}
insertIfVar(use_with_regs.begin(), use_with_regs.end(), use);
insertIfVar(def_with_regs.begin(), def_with_regs.end(), def);
use.insert(use_with_regs.begin(), use_with_regs.end());
def.insert(def_with_regs.begin(), def_with_regs.end());
}
@@ -145,6 +179,7 @@ private:
vector<SAPFOR::Argument*>& formal_parameters;
const map<string, FuncInfo*>& funcByName;
const set<SAPFOR::Argument*>& shared_regs;
public:
bool updateJumpStatus()
{
@@ -249,30 +284,34 @@ public:
for (SAPFOR::Argument* arg : use)
{
bool this_block = usedByThisBlock.find(arg) != usedByThisBlock.end();
if (!this_block)
if(arg && (arg->getType() == SAPFOR::CFG_ARG_TYPE::VAR ||
(arg->getType() == SAPFOR::CFG_ARG_TYPE::REG && shared_regs.find(arg) != shared_regs.end())))
{
auto data_it = data.find(arg);
bool this_block = usedByThisBlock.find(arg) != usedByThisBlock.end();
if (data_it == data.end())
printInternalError(convertFileName(__FILE__).c_str(), __LINE__);
inserted |= bb->addLiveIn({ *data_it });
}
else
{
auto in_it = in.find(arg);
bool skip = false;
if (in_it != in.end())
if (!this_block)
{
if (in_it->second.size() == 1 && *(in_it->second.begin()) == bb)
skip = true; // nothing to do, inserted = false
else
bb->removeLiveIn(arg);
auto data_it = data.find(arg);
if (data_it == data.end())
printInternalError(convertFileName(__FILE__).c_str(), __LINE__);
inserted |= bb->addLiveIn({ *data_it });
}
else
{
auto in_it = in.find(arg);
bool skip = false;
if (in_it != in.end())
{
if (in_it->second.size() == 1 && *(in_it->second.begin()) == bb)
skip = true; // nothing to do, inserted = false
else
bb->removeLiveIn(arg);
}
if(!skip)
inserted |= bb->addLiveIn({ { arg, { bb } } });
}
if(!skip)
inserted |= bb->addLiveIn({ { arg, { bb } } });
}
}
@@ -305,10 +344,12 @@ public:
DeadCodeAnalysisNode(SAPFOR::BasicBlock* block,
vector<SAPFOR::Argument*>& formal_parameters,
const map<string, FuncInfo*>& funcByName)
const map<string, FuncInfo*>& funcByName,
const set<SAPFOR::Argument*>& shared_regs)
:
formal_parameters(formal_parameters),
funcByName(funcByName)
funcByName(funcByName),
shared_regs(shared_regs)
{
setBlock(block);
useful.resize(block->getInstructions().size(), false);
@@ -322,16 +363,20 @@ class DeadCodeAnalysis : public BackwardDataFlowAnalysis<DeadCodeAnalysisNode>
protected:
vector<SAPFOR::Argument*>& formal_parameters;
const map<string, FuncInfo*>& funcByName;
const set<SAPFOR::Argument*>& shared_regs;
DeadCodeAnalysisNode* createNode(SAPFOR::BasicBlock* block) override
{
return new DeadCodeAnalysisNode(block, formal_parameters, funcByName);
return new DeadCodeAnalysisNode(block, formal_parameters, funcByName, shared_regs);
}
public:
DeadCodeAnalysis(vector<SAPFOR::Argument*>& formal_parameters, const map<string, FuncInfo*>& funcByName)
DeadCodeAnalysis(vector<SAPFOR::Argument*>& formal_parameters,
const map<string, FuncInfo*>& funcByName,
const set<SAPFOR::Argument*>& shared_regs)
:
formal_parameters(formal_parameters),
funcByName(funcByName)
funcByName(funcByName),
shared_regs(shared_regs)
{ }
};
@@ -403,8 +448,10 @@ void removeDeadCode(SgStatement* func,
cfg_pair.second.erase(remove_unreachable_it, cfg_pair.second.end());
#if DEBUG_IR
dumpCFG({ cfg_pair }, false);
#endif
// detect useless code
vector<SAPFOR::Argument*> func_parameters(cfg_pair.first->funcParams.countOfPars, NULL);
map<string, FuncInfo*> funcByName;
@@ -412,8 +459,11 @@ void removeDeadCode(SgStatement* func,
for (auto& byFile : allFuncs)
for (auto byFunc : byFile.second)
funcByName[byFunc->funcName] = byFunc;
set<SAPFOR::Argument*> shared_regs;
fillSharedRegs({ cfg_pair }, shared_regs);
DeadCodeAnalysis analysis_object(func_parameters, funcByName);
DeadCodeAnalysis analysis_object(func_parameters, funcByName, shared_regs);
analysis_object.fit(cfg_pair.second);
analysis_object.analyze();