1 //===- LowerPacked.cpp - Implementation of LowerPacked Transform ---------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Brad Jones and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements lowering Packed datatypes into more primitive
11 // Packed datatypes, and finally to scalar operations.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/Scalar.h"
16 #include "llvm/Argument.h"
17 #include "llvm/Constants.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Function.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Support/InstVisitor.h"
23 #include "llvm/ADT/StringExtras.h"
33 /// This pass converts packed operators to an
34 /// equivalent operations on smaller packed data, to possibly
35 /// scalar operations. Currently it supports lowering
36 /// to scalar operations.
38 /// @brief Transforms packed instructions to simpler instructions.
40 class LowerPacked : public FunctionPass, public InstVisitor<LowerPacked> {
42 /// @brief Lowers packed operations to scalar operations.
43 /// @param F The fuction to process
44 virtual bool runOnFunction(Function &F);
46 /// @brief Lowers packed load instructions.
47 /// @param LI the load instruction to convert
48 void visitLoadInst(LoadInst& LI);
50 /// @brief Lowers packed store instructions.
51 /// @param SI the store instruction to convert
52 void visitStoreInst(StoreInst& SI);
54 /// @brief Lowers packed binary operations.
55 /// @param BO the binary operator to convert
56 void visitBinaryOperator(BinaryOperator& BO);
58 /// @brief Lowers packed select instructions.
59 /// @param SELI the select operator to convert
60 void visitSelectInst(SelectInst& SELI);
62 /// @brief Lowers packed extractelement instructions.
63 /// @param EI the extractelement operator to convert
64 void visitExtractElementInst(ExtractElementInst& EE);
66 /// @brief Lowers packed insertelement instructions.
67 /// @param EI the insertelement operator to convert
68 void visitInsertElementInst(InsertElementInst& IE);
70 /// This function asserts if the instruction is a PackedType but
71 /// is handled by another function.
73 /// @brief Asserts if PackedType instruction is not handled elsewhere.
74 /// @param I the unhandled instruction
75 void visitInstruction(Instruction &I)
77 if(isa<PackedType>(I.getType())) {
78 std::cerr << "Unhandled Instruction with Packed ReturnType: " <<
83 /// @brief Retrieves lowered values for a packed value.
84 /// @param val the packed value
85 /// @return the lowered values
86 std::vector<Value*>& getValues(Value* val);
88 /// @brief Sets lowered values for a packed value.
89 /// @param val the packed value
90 /// @param values the corresponding lowered values
91 void setValues(Value* val,const std::vector<Value*>& values);
94 /// @brief whether we changed the function or not
97 /// @brief a map from old packed values to new smaller packed values
98 std::map<Value*,std::vector<Value*> > packedToScalarMap;
100 /// Instructions in the source program to get rid of
101 /// after we do a pass (the old packed instructions)
102 std::vector<Instruction*> instrsToRemove;
105 RegisterPass<LowerPacked>
107 "lowers packed operations to operations on smaller packed datatypes");
111 FunctionPass *llvm::createLowerPackedPass() { return new LowerPacked(); }
114 // This function sets lowered values for a corresponding
115 // packed value. Note, in the case of a forward reference
116 // getValues(Value*) will have already been called for
117 // the packed parameter. This function will then replace
118 // all references in the in the function of the "dummy"
119 // value the previous getValues(Value*) call
120 // returned with actual references.
121 void LowerPacked::setValues(Value* value,const std::vector<Value*>& values)
123 std::map<Value*,std::vector<Value*> >::iterator it =
124 packedToScalarMap.lower_bound(value);
125 if (it == packedToScalarMap.end() || it->first != value) {
126 // there was not a forward reference to this element
127 packedToScalarMap.insert(it,std::make_pair(value,values));
130 // replace forward declarations with actual definitions
131 assert(it->second.size() == values.size() &&
132 "Error forward refences and actual definition differ in size");
133 for (unsigned i = 0, e = values.size(); i != e; ++i) {
134 // replace and get rid of old forward references
135 it->second[i]->replaceAllUsesWith(values[i]);
136 delete it->second[i];
137 it->second[i] = values[i];
142 // This function will examine the packed value parameter
143 // and if it is a packed constant or a forward reference
144 // properly create the lowered values needed. Otherwise
145 // it will simply retreive values from a
146 // setValues(Value*,const std::vector<Value*>&)
147 // call. Failing both of these cases, it will abort
149 std::vector<Value*>& LowerPacked::getValues(Value* value)
151 assert(isa<PackedType>(value->getType()) &&
152 "Value must be PackedType");
154 // reject further processing if this one has
155 // already been handled
156 std::map<Value*,std::vector<Value*> >::iterator it =
157 packedToScalarMap.lower_bound(value);
158 if (it != packedToScalarMap.end() && it->first == value) {
162 if (ConstantPacked* CP = dyn_cast<ConstantPacked>(value)) {
163 // non-zero constant case
164 std::vector<Value*> results;
165 results.reserve(CP->getNumOperands());
166 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) {
167 results.push_back(CP->getOperand(i));
169 return packedToScalarMap.insert(it,
170 std::make_pair(value,results))->second;
172 else if (ConstantAggregateZero* CAZ =
173 dyn_cast<ConstantAggregateZero>(value)) {
175 const PackedType* PKT = cast<PackedType>(CAZ->getType());
176 std::vector<Value*> results;
177 results.reserve(PKT->getNumElements());
179 Constant* C = Constant::getNullValue(PKT->getElementType());
180 for (unsigned i = 0, e = PKT->getNumElements(); i != e; ++i) {
181 results.push_back(C);
183 return packedToScalarMap.insert(it,
184 std::make_pair(value,results))->second;
186 else if (isa<Instruction>(value)) {
188 const PackedType* PKT = cast<PackedType>(value->getType());
189 std::vector<Value*> results;
190 results.reserve(PKT->getNumElements());
192 for (unsigned i = 0, e = PKT->getNumElements(); i != e; ++i) {
193 results.push_back(new Argument(PKT->getElementType()));
195 return packedToScalarMap.insert(it,
196 std::make_pair(value,results))->second;
199 // we don't know what it is, and we are trying to retrieve
201 assert(false && "Unhandled PackedType value");
206 void LowerPacked::visitLoadInst(LoadInst& LI)
208 // Make sure what we are dealing with is a packed type
209 if (const PackedType* PKT = dyn_cast<PackedType>(LI.getType())) {
210 // Initialization, Idx is needed for getelementptr needed later
211 std::vector<Value*> Idx(2);
212 Idx[0] = ConstantInt::get(Type::UIntTy,0);
214 ArrayType* AT = ArrayType::get(PKT->getContainedType(0),
215 PKT->getNumElements());
216 PointerType* APT = PointerType::get(AT);
218 // Cast the packed type to an array
219 Value* array = new CastInst(LI.getPointerOperand(),
224 // Convert this load into num elements number of loads
225 std::vector<Value*> values;
226 values.reserve(PKT->getNumElements());
228 for (unsigned i = 0, e = PKT->getNumElements(); i != e; ++i) {
229 // Calculate the second index we will need
230 Idx[1] = ConstantInt::get(Type::UIntTy,i);
233 Value* val = new GetElementPtrInst(array,
239 // generate the new load and save the result in packedToScalar map
240 values.push_back(new LoadInst(val,
241 LI.getName()+"."+utostr(i),
246 setValues(&LI,values);
248 instrsToRemove.push_back(&LI);
252 void LowerPacked::visitBinaryOperator(BinaryOperator& BO)
254 // Make sure both operands are PackedTypes
255 if (isa<PackedType>(BO.getOperand(0)->getType())) {
256 std::vector<Value*>& op0Vals = getValues(BO.getOperand(0));
257 std::vector<Value*>& op1Vals = getValues(BO.getOperand(1));
258 std::vector<Value*> result;
259 assert((op0Vals.size() == op1Vals.size()) &&
260 "The two packed operand to scalar maps must be equal in size.");
262 result.reserve(op0Vals.size());
264 // generate the new binary op and save the result
265 for (unsigned i = 0; i != op0Vals.size(); ++i) {
266 result.push_back(BinaryOperator::create(BO.getOpcode(),
274 setValues(&BO,result);
276 instrsToRemove.push_back(&BO);
280 void LowerPacked::visitStoreInst(StoreInst& SI)
282 if (const PackedType* PKT =
283 dyn_cast<PackedType>(SI.getOperand(0)->getType())) {
284 // We will need this for getelementptr
285 std::vector<Value*> Idx(2);
286 Idx[0] = ConstantInt::get(Type::UIntTy,0);
288 ArrayType* AT = ArrayType::get(PKT->getContainedType(0),
289 PKT->getNumElements());
290 PointerType* APT = PointerType::get(AT);
292 // cast the packed to an array type
293 Value* array = new CastInst(SI.getPointerOperand(),
297 std::vector<Value*>& values = getValues(SI.getOperand(0));
299 assert((values.size() == PKT->getNumElements()) &&
300 "Scalar must have the same number of elements as Packed Type");
302 for (unsigned i = 0, e = PKT->getNumElements(); i != e; ++i) {
303 // Generate the indices for getelementptr
304 Idx[1] = ConstantInt::get(Type::UIntTy,i);
305 Value* val = new GetElementPtrInst(array,
310 new StoreInst(values[i], val, SI.isVolatile(),&SI);
314 instrsToRemove.push_back(&SI);
318 void LowerPacked::visitSelectInst(SelectInst& SELI)
320 // Make sure both operands are PackedTypes
321 if (isa<PackedType>(SELI.getType())) {
322 std::vector<Value*>& op0Vals = getValues(SELI.getTrueValue());
323 std::vector<Value*>& op1Vals = getValues(SELI.getFalseValue());
324 std::vector<Value*> result;
326 assert((op0Vals.size() == op1Vals.size()) &&
327 "The two packed operand to scalar maps must be equal in size.");
329 for (unsigned i = 0; i != op0Vals.size(); ++i) {
330 result.push_back(new SelectInst(SELI.getCondition(),
333 SELI.getName()+ "." + utostr(i),
337 setValues(&SELI,result);
339 instrsToRemove.push_back(&SELI);
343 void LowerPacked::visitExtractElementInst(ExtractElementInst& EI)
345 std::vector<Value*>& op0Vals = getValues(EI.getOperand(0));
346 const PackedType *PTy = cast<PackedType>(EI.getOperand(0)->getType());
347 Value *op1 = EI.getOperand(1);
349 if (ConstantInt *C = dyn_cast<ConstantInt>(op1)) {
350 EI.replaceAllUsesWith(op0Vals[C->getZExtValue()]);
353 new AllocaInst(PTy->getElementType(),
354 ConstantInt::get(Type::UIntTy, PTy->getNumElements()),
355 EI.getName() + ".alloca",
356 EI.getParent()->getParent()->getEntryBlock().begin());
357 for (unsigned i = 0; i < PTy->getNumElements(); ++i) {
358 GetElementPtrInst *GEP =
359 new GetElementPtrInst(alloca, ConstantInt::get(Type::UIntTy, i),
361 new StoreInst(op0Vals[i], GEP, &EI);
363 GetElementPtrInst *GEP =
364 new GetElementPtrInst(alloca, op1, EI.getName() + ".ge", &EI);
365 LoadInst *load = new LoadInst(GEP, EI.getName() + ".load", &EI);
366 EI.replaceAllUsesWith(load);
370 instrsToRemove.push_back(&EI);
373 void LowerPacked::visitInsertElementInst(InsertElementInst& IE)
375 std::vector<Value*>& Vals = getValues(IE.getOperand(0));
376 Value *Elt = IE.getOperand(1);
377 Value *Idx = IE.getOperand(2);
378 std::vector<Value*> result;
379 result.reserve(Vals.size());
381 if (ConstantInt *C = dyn_cast<ConstantInt>(Idx)) {
382 unsigned idxVal = C->getZExtValue();
383 for (unsigned i = 0; i != Vals.size(); ++i) {
384 result.push_back(i == idxVal ? Elt : Vals[i]);
387 for (unsigned i = 0; i != Vals.size(); ++i) {
389 new SetCondInst(Instruction::SetEQ, Idx,
390 ConstantInt::get(Type::UIntTy, i),
393 new SelectInst(setcc, Elt, Vals[i], "select", &IE);
394 result.push_back(select);
398 setValues(&IE, result);
400 instrsToRemove.push_back(&IE);
403 bool LowerPacked::runOnFunction(Function& F)
408 // Does three passes:
409 // Pass 1) Converts Packed Operations to
410 // new Packed Operations on smaller
414 // Pass 2) Drop all references
415 std::for_each(instrsToRemove.begin(),
416 instrsToRemove.end(),
417 std::mem_fun(&Instruction::dropAllReferences));
419 // Pass 3) Delete the Instructions to remove aka packed instructions
420 for (std::vector<Instruction*>::iterator i = instrsToRemove.begin(),
421 e = instrsToRemove.end();
423 (*i)->getParent()->getInstList().erase(*i);
427 packedToScalarMap.clear();
428 instrsToRemove.clear();