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dead code: improve perfomance by removing unnecessary checks

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This commit is contained in:
Mikhail Kocharmin
2024-04-07 17:40:30 +03:00
parent e33fe45a2b
commit 9bc4fa246c
1 changed files with 7 additions and 50 deletions
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57
sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp
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@@ -16,39 +16,6 @@ using std::remove_if;
#define PRINT_USELESS_STATEMENTS 1 #define PRINT_USELESS_STATEMENTS 1
#define DEBUG_IR 0 #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, static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instruction* instr,
set<SAPFOR::Argument*>& use, set<SAPFOR::Argument*>& def, set<SAPFOR::Argument*>& use, set<SAPFOR::Argument*>& def,
vector<SAPFOR::Argument*>& formal_parameters, vector<SAPFOR::Argument*>& formal_parameters,
@@ -179,7 +146,6 @@ private:
vector<SAPFOR::Argument*>& formal_parameters; vector<SAPFOR::Argument*>& formal_parameters;
const map<string, FuncInfo*>& funcByName; const map<string, FuncInfo*>& funcByName;
const set<SAPFOR::Argument*>& shared_regs;
public: public:
bool updateJumpStatus() bool updateJumpStatus()
{ {
@@ -284,8 +250,7 @@ public:
for (SAPFOR::Argument* arg : use) for (SAPFOR::Argument* arg : use)
{ {
if(arg && (arg->getType() == SAPFOR::CFG_ARG_TYPE::VAR || if(arg && (arg->getType() == SAPFOR::CFG_ARG_TYPE::VAR || arg->getType() == SAPFOR::CFG_ARG_TYPE::REG))
(arg->getType() == SAPFOR::CFG_ARG_TYPE::REG && shared_regs.find(arg) != shared_regs.end())))
{ {
bool this_block = usedByThisBlock.find(arg) != usedByThisBlock.end(); bool this_block = usedByThisBlock.find(arg) != usedByThisBlock.end();
@@ -344,12 +309,10 @@ public:
DeadCodeAnalysisNode(SAPFOR::BasicBlock* block, DeadCodeAnalysisNode(SAPFOR::BasicBlock* block,
vector<SAPFOR::Argument*>& formal_parameters, 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), formal_parameters(formal_parameters),
funcByName(funcByName), funcByName(funcByName)
shared_regs(shared_regs)
{ {
setBlock(block); setBlock(block);
useful.resize(block->getInstructions().size(), false); useful.resize(block->getInstructions().size(), false);
@@ -363,20 +326,17 @@ class DeadCodeAnalysis : public BackwardDataFlowAnalysis<DeadCodeAnalysisNode>
protected: protected:
vector<SAPFOR::Argument*>& formal_parameters; vector<SAPFOR::Argument*>& formal_parameters;
const map<string, FuncInfo*>& funcByName; const map<string, FuncInfo*>& funcByName;
const set<SAPFOR::Argument*>& shared_regs;
DeadCodeAnalysisNode* createNode(SAPFOR::BasicBlock* block) override DeadCodeAnalysisNode* createNode(SAPFOR::BasicBlock* block) override
{ {
return new DeadCodeAnalysisNode(block, formal_parameters, funcByName, shared_regs); return new DeadCodeAnalysisNode(block, formal_parameters, funcByName);
} }
public: public:
DeadCodeAnalysis(vector<SAPFOR::Argument*>& formal_parameters, DeadCodeAnalysis(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), formal_parameters(formal_parameters),
funcByName(funcByName), funcByName(funcByName)
shared_regs(shared_regs)
{ } { }
}; };
@@ -459,11 +419,8 @@ void removeDeadCode(SgStatement* func,
for (auto& byFile : allFuncs) for (auto& byFile : allFuncs)
for (auto byFunc : byFile.second) for (auto byFunc : byFile.second)
funcByName[byFunc->funcName] = byFunc; funcByName[byFunc->funcName] = byFunc;
set<SAPFOR::Argument*> shared_regs;
fillSharedRegs({ cfg_pair }, shared_regs);
DeadCodeAnalysis analysis_object(func_parameters, funcByName, shared_regs); DeadCodeAnalysis analysis_object(func_parameters, funcByName);
analysis_object.fit(cfg_pair.second); analysis_object.fit(cfg_pair.second);
analysis_object.analyze(); analysis_object.analyze();