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/Support/Streams.h"
24 #include "llvm/ADT/StringExtras.h"
32 /// This pass converts packed operators to an
33 /// equivalent operations on smaller packed data, to possibly
34 /// scalar operations. Currently it supports lowering
35 /// to scalar operations.
37 /// @brief Transforms packed instructions to simpler instructions.
39 class LowerPacked : public FunctionPass, public InstVisitor<LowerPacked> {
41 /// @brief Lowers packed operations to scalar operations.
42 /// @param F The fuction to process
43 virtual bool runOnFunction(Function &F);
45 /// @brief Lowers packed load instructions.
46 /// @param LI the load instruction to convert
47 void visitLoadInst(LoadInst& LI);
49 /// @brief Lowers packed store instructions.
50 /// @param SI the store instruction to convert
51 void visitStoreInst(StoreInst& SI);
53 /// @brief Lowers packed binary operations.
54 /// @param BO the binary operator to convert
55 void visitBinaryOperator(BinaryOperator& BO);
57 /// @brief Lowers packed icmp operations.
58 /// @param CI the icmp operator to convert
59 void visitICmpInst(ICmpInst& IC);
61 /// @brief Lowers packed select instructions.
62 /// @param SELI the select operator to convert
63 void visitSelectInst(SelectInst& SELI);
65 /// @brief Lowers packed extractelement instructions.
66 /// @param EI the extractelement operator to convert
67 void visitExtractElementInst(ExtractElementInst& EE);
69 /// @brief Lowers packed insertelement instructions.
70 /// @param EI the insertelement operator to convert
71 void visitInsertElementInst(InsertElementInst& IE);
73 /// This function asserts if the instruction is a PackedType but
74 /// is handled by another function.
76 /// @brief Asserts if PackedType instruction is not handled elsewhere.
77 /// @param I the unhandled instruction
78 void visitInstruction(Instruction &I) {
79 if (isa<PackedType>(I.getType()))
80 cerr << "Unhandled Instruction with Packed ReturnType: " << I << '\n';
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 pointer to packed type to an equivalent array
219 Value* array = new BitCastInst(LI.getPointerOperand(), APT,
220 LI.getName() + ".a", &LI);
222 // Convert this load into num elements number of loads
223 std::vector<Value*> values;
224 values.reserve(PKT->getNumElements());
226 for (unsigned i = 0, e = PKT->getNumElements(); i != e; ++i) {
227 // Calculate the second index we will need
228 Idx[1] = ConstantInt::get(Type::UIntTy,i);
231 Value* val = new GetElementPtrInst(array,
237 // generate the new load and save the result in packedToScalar map
238 values.push_back(new LoadInst(val, LI.getName()+"."+utostr(i),
239 LI.isVolatile(), &LI));
242 setValues(&LI,values);
244 instrsToRemove.push_back(&LI);
248 void LowerPacked::visitBinaryOperator(BinaryOperator& BO)
250 // Make sure both operands are PackedTypes
251 if (isa<PackedType>(BO.getOperand(0)->getType())) {
252 std::vector<Value*>& op0Vals = getValues(BO.getOperand(0));
253 std::vector<Value*>& op1Vals = getValues(BO.getOperand(1));
254 std::vector<Value*> result;
255 assert((op0Vals.size() == op1Vals.size()) &&
256 "The two packed operand to scalar maps must be equal in size.");
258 result.reserve(op0Vals.size());
260 // generate the new binary op and save the result
261 for (unsigned i = 0; i != op0Vals.size(); ++i) {
262 result.push_back(BinaryOperator::create(BO.getOpcode(),
270 setValues(&BO,result);
272 instrsToRemove.push_back(&BO);
276 void LowerPacked::visitICmpInst(ICmpInst& IC)
278 // Make sure both operands are PackedTypes
279 if (isa<PackedType>(IC.getOperand(0)->getType())) {
280 std::vector<Value*>& op0Vals = getValues(IC.getOperand(0));
281 std::vector<Value*>& op1Vals = getValues(IC.getOperand(1));
282 std::vector<Value*> result;
283 assert((op0Vals.size() == op1Vals.size()) &&
284 "The two packed operand to scalar maps must be equal in size.");
286 result.reserve(op0Vals.size());
288 // generate the new binary op and save the result
289 for (unsigned i = 0; i != op0Vals.size(); ++i) {
290 result.push_back(CmpInst::create(IC.getOpcode(),
299 setValues(&IC,result);
301 instrsToRemove.push_back(&IC);
305 void LowerPacked::visitStoreInst(StoreInst& SI)
307 if (const PackedType* PKT =
308 dyn_cast<PackedType>(SI.getOperand(0)->getType())) {
309 // We will need this for getelementptr
310 std::vector<Value*> Idx(2);
311 Idx[0] = ConstantInt::get(Type::UIntTy,0);
313 ArrayType* AT = ArrayType::get(PKT->getContainedType(0),
314 PKT->getNumElements());
315 PointerType* APT = PointerType::get(AT);
317 // Cast the pointer to packed to an array of equivalent type
318 Value* array = new BitCastInst(SI.getPointerOperand(), APT,
321 std::vector<Value*>& values = getValues(SI.getOperand(0));
323 assert((values.size() == PKT->getNumElements()) &&
324 "Scalar must have the same number of elements as Packed Type");
326 for (unsigned i = 0, e = PKT->getNumElements(); i != e; ++i) {
327 // Generate the indices for getelementptr
328 Idx[1] = ConstantInt::get(Type::UIntTy,i);
329 Value* val = new GetElementPtrInst(array,
334 new StoreInst(values[i], val, SI.isVolatile(),&SI);
338 instrsToRemove.push_back(&SI);
342 void LowerPacked::visitSelectInst(SelectInst& SELI)
344 // Make sure both operands are PackedTypes
345 if (isa<PackedType>(SELI.getType())) {
346 std::vector<Value*>& op0Vals = getValues(SELI.getTrueValue());
347 std::vector<Value*>& op1Vals = getValues(SELI.getFalseValue());
348 std::vector<Value*> result;
350 assert((op0Vals.size() == op1Vals.size()) &&
351 "The two packed operand to scalar maps must be equal in size.");
353 for (unsigned i = 0; i != op0Vals.size(); ++i) {
354 result.push_back(new SelectInst(SELI.getCondition(),
357 SELI.getName()+ "." + utostr(i),
361 setValues(&SELI,result);
363 instrsToRemove.push_back(&SELI);
367 void LowerPacked::visitExtractElementInst(ExtractElementInst& EI)
369 std::vector<Value*>& op0Vals = getValues(EI.getOperand(0));
370 const PackedType *PTy = cast<PackedType>(EI.getOperand(0)->getType());
371 Value *op1 = EI.getOperand(1);
373 if (ConstantInt *C = dyn_cast<ConstantInt>(op1)) {
374 EI.replaceAllUsesWith(op0Vals[C->getZExtValue()]);
377 new AllocaInst(PTy->getElementType(),
378 ConstantInt::get(Type::UIntTy, PTy->getNumElements()),
379 EI.getName() + ".alloca",
380 EI.getParent()->getParent()->getEntryBlock().begin());
381 for (unsigned i = 0; i < PTy->getNumElements(); ++i) {
382 GetElementPtrInst *GEP =
383 new GetElementPtrInst(alloca, ConstantInt::get(Type::UIntTy, i),
385 new StoreInst(op0Vals[i], GEP, &EI);
387 GetElementPtrInst *GEP =
388 new GetElementPtrInst(alloca, op1, EI.getName() + ".ge", &EI);
389 LoadInst *load = new LoadInst(GEP, EI.getName() + ".load", &EI);
390 EI.replaceAllUsesWith(load);
394 instrsToRemove.push_back(&EI);
397 void LowerPacked::visitInsertElementInst(InsertElementInst& IE)
399 std::vector<Value*>& Vals = getValues(IE.getOperand(0));
400 Value *Elt = IE.getOperand(1);
401 Value *Idx = IE.getOperand(2);
402 std::vector<Value*> result;
403 result.reserve(Vals.size());
405 if (ConstantInt *C = dyn_cast<ConstantInt>(Idx)) {
406 unsigned idxVal = C->getZExtValue();
407 for (unsigned i = 0; i != Vals.size(); ++i) {
408 result.push_back(i == idxVal ? Elt : Vals[i]);
411 for (unsigned i = 0; i != Vals.size(); ++i) {
413 new ICmpInst(ICmpInst::ICMP_EQ, Idx,
414 ConstantInt::get(Type::UIntTy, i),
417 new SelectInst(icmp, Elt, Vals[i], "select", &IE);
418 result.push_back(select);
422 setValues(&IE, result);
424 instrsToRemove.push_back(&IE);
427 bool LowerPacked::runOnFunction(Function& F)
432 // Does three passes:
433 // Pass 1) Converts Packed Operations to
434 // new Packed Operations on smaller
438 // Pass 2) Drop all references
439 std::for_each(instrsToRemove.begin(),
440 instrsToRemove.end(),
441 std::mem_fun(&Instruction::dropAllReferences));
443 // Pass 3) Delete the Instructions to remove aka packed instructions
444 for (std::vector<Instruction*>::iterator i = instrsToRemove.begin(),
445 e = instrsToRemove.end();
447 (*i)->getParent()->getInstList().erase(*i);
451 packedToScalarMap.clear();
452 instrsToRemove.clear();