1 //===-- PredicateInfo.cpp - PredicateInfo Builder--------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------===//
10 // This file implements the PredicateInfo class.
12 //===----------------------------------------------------------------===//
14 #include "llvm/Transforms/Utils/PredicateInfo.h"
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/DepthFirstIterator.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/Analysis/AssumptionCache.h"
21 #include "llvm/Analysis/CFG.h"
22 #include "llvm/Analysis/OrderedBasicBlock.h"
23 #include "llvm/IR/AssemblyAnnotationWriter.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/IR/Dominators.h"
26 #include "llvm/IR/GlobalVariable.h"
27 #include "llvm/IR/IRBuilder.h"
28 #include "llvm/IR/IntrinsicInst.h"
29 #include "llvm/IR/LLVMContext.h"
30 #include "llvm/IR/Metadata.h"
31 #include "llvm/IR/Module.h"
32 #include "llvm/IR/PatternMatch.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/DebugCounter.h"
35 #include "llvm/Support/FormattedStream.h"
36 #include "llvm/Transforms/Scalar.h"
38 #define DEBUG_TYPE "predicateinfo"
40 using namespace PatternMatch;
41 using namespace llvm::PredicateInfoClasses;
43 INITIALIZE_PASS_BEGIN(PredicateInfoPrinterLegacyPass, "print-predicateinfo",
44 "PredicateInfo Printer", false, false)
45 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
46 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
47 INITIALIZE_PASS_END(PredicateInfoPrinterLegacyPass, "print-predicateinfo",
48 "PredicateInfo Printer", false, false)
49 static cl::opt<bool> VerifyPredicateInfo(
50 "verify-predicateinfo", cl::init(false), cl::Hidden,
51 cl::desc("Verify PredicateInfo in legacy printer pass."));
53 DEBUG_COUNTER(RenameCounter, "predicateinfo-rename",
54 "Controls which variables are renamed with predicateinfo")
55 // Given a predicate info that is a type of branching terminator, get the
57 const BasicBlock *getBranchBlock(const PredicateBase *PB) {
58 assert(isa<PredicateWithEdge>(PB) &&
59 "Only branches and switches should have PHIOnly defs that "
60 "require branch blocks.");
61 return cast<PredicateWithEdge>(PB)->From;
64 // Given a predicate info that is a type of branching terminator, get the
65 // branching terminator.
66 static Instruction *getBranchTerminator(const PredicateBase *PB) {
67 assert(isa<PredicateWithEdge>(PB) &&
68 "Not a predicate info type we know how to get a terminator from.");
69 return cast<PredicateWithEdge>(PB)->From->getTerminator();
72 // Given a predicate info that is a type of branching terminator, get the
73 // edge this predicate info represents
74 const std::pair<BasicBlock *, BasicBlock *>
75 getBlockEdge(const PredicateBase *PB) {
76 assert(isa<PredicateWithEdge>(PB) &&
77 "Not a predicate info type we know how to get an edge from.");
78 const auto *PEdge = cast<PredicateWithEdge>(PB);
79 return std::make_pair(PEdge->From, PEdge->To);
84 namespace PredicateInfoClasses {
86 // Operations that must appear first in the block.
88 // Operations that are somewhere in the middle of the block, and are sorted on
91 // Operations that must appear last in a block, like successor phi node uses.
95 // Associate global and local DFS info with defs and uses, so we can sort them
96 // into a global domination ordering.
100 unsigned int LocalNum = LN_Middle;
101 // Only one of Def or Use will be set.
102 Value *Def = nullptr;
104 // Neither PInfo nor EdgeOnly participate in the ordering
105 PredicateBase *PInfo = nullptr;
106 bool EdgeOnly = false;
109 // This compares ValueDFS structures, creating OrderedBasicBlocks where
110 // necessary to compare uses/defs in the same block. Doing so allows us to walk
111 // the minimum number of instructions necessary to compute our def/use ordering.
112 struct ValueDFS_Compare {
113 DenseMap<const BasicBlock *, std::unique_ptr<OrderedBasicBlock>> &OBBMap;
115 DenseMap<const BasicBlock *, std::unique_ptr<OrderedBasicBlock>> &OBBMap)
117 bool operator()(const ValueDFS &A, const ValueDFS &B) const {
120 // The only case we can't directly compare them is when they in the same
121 // block, and both have localnum == middle. In that case, we have to use
122 // comesbefore to see what the real ordering is, because they are in the
125 bool SameBlock = std::tie(A.DFSIn, A.DFSOut) == std::tie(B.DFSIn, B.DFSOut);
127 // We want to put the def that will get used for a given set of phi uses,
128 // before those phi uses.
129 // So we sort by edge, then by def.
130 // Note that only phi nodes uses and defs can come last.
131 if (SameBlock && A.LocalNum == LN_Last && B.LocalNum == LN_Last)
132 return comparePHIRelated(A, B);
134 if (!SameBlock || A.LocalNum != LN_Middle || B.LocalNum != LN_Middle)
135 return std::tie(A.DFSIn, A.DFSOut, A.LocalNum, A.Def, A.U) <
136 std::tie(B.DFSIn, B.DFSOut, B.LocalNum, B.Def, B.U);
137 return localComesBefore(A, B);
140 // For a phi use, or a non-materialized def, return the edge it represents.
141 const std::pair<BasicBlock *, BasicBlock *>
142 getBlockEdge(const ValueDFS &VD) const {
143 if (!VD.Def && VD.U) {
144 auto *PHI = cast<PHINode>(VD.U->getUser());
145 return std::make_pair(PHI->getIncomingBlock(*VD.U), PHI->getParent());
147 // This is really a non-materialized def.
148 return ::getBlockEdge(VD.PInfo);
151 // For two phi related values, return the ordering.
152 bool comparePHIRelated(const ValueDFS &A, const ValueDFS &B) const {
153 auto &ABlockEdge = getBlockEdge(A);
154 auto &BBlockEdge = getBlockEdge(B);
155 // Now sort by block edge and then defs before uses.
156 return std::tie(ABlockEdge, A.Def, A.U) < std::tie(BBlockEdge, B.Def, B.U);
159 // Get the definition of an instruction that occurs in the middle of a block.
160 Value *getMiddleDef(const ValueDFS &VD) const {
163 // It's possible for the defs and uses to be null. For branches, the local
164 // numbering will say the placed predicaeinfos should go first (IE
165 // LN_beginning), so we won't be in this function. For assumes, we will end
166 // up here, beause we need to order the def we will place relative to the
167 // assume. So for the purpose of ordering, we pretend the def is the assume
168 // because that is where we will insert the info.
171 "No def, no use, and no predicateinfo should not occur");
172 assert(isa<PredicateAssume>(VD.PInfo) &&
173 "Middle of block should only occur for assumes");
174 return cast<PredicateAssume>(VD.PInfo)->AssumeInst;
179 // Return either the Def, if it's not null, or the user of the Use, if the def
181 const Instruction *getDefOrUser(const Value *Def, const Use *U) const {
183 return cast<Instruction>(Def);
184 return cast<Instruction>(U->getUser());
187 // This performs the necessary local basic block ordering checks to tell
188 // whether A comes before B, where both are in the same basic block.
189 bool localComesBefore(const ValueDFS &A, const ValueDFS &B) const {
190 auto *ADef = getMiddleDef(A);
191 auto *BDef = getMiddleDef(B);
193 // See if we have real values or uses. If we have real values, we are
194 // guaranteed they are instructions or arguments. No matter what, we are
195 // guaranteed they are in the same block if they are instructions.
196 auto *ArgA = dyn_cast_or_null<Argument>(ADef);
197 auto *ArgB = dyn_cast_or_null<Argument>(BDef);
204 return ArgA->getArgNo() < ArgB->getArgNo();
206 auto *AInst = getDefOrUser(ADef, A.U);
207 auto *BInst = getDefOrUser(BDef, B.U);
209 auto *BB = AInst->getParent();
210 auto LookupResult = OBBMap.find(BB);
211 if (LookupResult != OBBMap.end())
212 return LookupResult->second->dominates(AInst, BInst);
214 auto Result = OBBMap.insert({BB, make_unique<OrderedBasicBlock>(BB)});
215 return Result.first->second->dominates(AInst, BInst);
219 } // namespace PredicateInfoClasses
221 bool PredicateInfo::stackIsInScope(const ValueDFSStack &Stack,
222 const ValueDFS &VDUse) const {
225 // If it's a phi only use, make sure it's for this phi node edge, and that the
226 // use is in a phi node. If it's anything else, and the top of the stack is
227 // EdgeOnly, we need to pop the stack. We deliberately sort phi uses next to
228 // the defs they must go with so that we can know it's time to pop the stack
229 // when we hit the end of the phi uses for a given def.
230 if (Stack.back().EdgeOnly) {
233 auto *PHI = dyn_cast<PHINode>(VDUse.U->getUser());
237 BasicBlock *EdgePred = PHI->getIncomingBlock(*VDUse.U);
238 if (EdgePred != getBranchBlock(Stack.back().PInfo))
241 // Use dominates, which knows how to handle edge dominance.
242 return DT.dominates(getBlockEdge(Stack.back().PInfo), *VDUse.U);
245 return (VDUse.DFSIn >= Stack.back().DFSIn &&
246 VDUse.DFSOut <= Stack.back().DFSOut);
249 void PredicateInfo::popStackUntilDFSScope(ValueDFSStack &Stack,
250 const ValueDFS &VD) {
251 while (!Stack.empty() && !stackIsInScope(Stack, VD))
255 // Convert the uses of Op into a vector of uses, associating global and local
256 // DFS info with each one.
257 void PredicateInfo::convertUsesToDFSOrdered(
258 Value *Op, SmallVectorImpl<ValueDFS> &DFSOrderedSet) {
259 for (auto &U : Op->uses()) {
260 if (auto *I = dyn_cast<Instruction>(U.getUser())) {
262 // Put the phi node uses in the incoming block.
264 if (auto *PN = dyn_cast<PHINode>(I)) {
265 IBlock = PN->getIncomingBlock(U);
266 // Make phi node users appear last in the incoming block
268 VD.LocalNum = LN_Last;
270 // If it's not a phi node use, it is somewhere in the middle of the
272 IBlock = I->getParent();
273 VD.LocalNum = LN_Middle;
275 DomTreeNode *DomNode = DT.getNode(IBlock);
276 // It's possible our use is in an unreachable block. Skip it if so.
279 VD.DFSIn = DomNode->getDFSNumIn();
280 VD.DFSOut = DomNode->getDFSNumOut();
282 DFSOrderedSet.push_back(VD);
287 // Collect relevant operations from Comparison that we may want to insert copies
289 void collectCmpOps(CmpInst *Comparison, SmallVectorImpl<Value *> &CmpOperands) {
290 auto *Op0 = Comparison->getOperand(0);
291 auto *Op1 = Comparison->getOperand(1);
294 CmpOperands.push_back(Comparison);
295 // Only want real values, not constants. Additionally, operands with one use
296 // are only being used in the comparison, which means they will not be useful
297 // for us to consider for predicateinfo.
299 if ((isa<Instruction>(Op0) || isa<Argument>(Op0)) && !Op0->hasOneUse())
300 CmpOperands.push_back(Op0);
301 if ((isa<Instruction>(Op1) || isa<Argument>(Op1)) && !Op1->hasOneUse())
302 CmpOperands.push_back(Op1);
305 // Add Op, PB to the list of value infos for Op, and mark Op to be renamed.
306 void PredicateInfo::addInfoFor(SmallPtrSetImpl<Value *> &OpsToRename, Value *Op,
308 OpsToRename.insert(Op);
309 auto &OperandInfo = getOrCreateValueInfo(Op);
310 AllInfos.push_back(PB);
311 OperandInfo.Infos.push_back(PB);
314 // Process an assume instruction and place relevant operations we want to rename
316 void PredicateInfo::processAssume(IntrinsicInst *II, BasicBlock *AssumeBB,
317 SmallPtrSetImpl<Value *> &OpsToRename) {
318 // See if we have a comparison we support
319 SmallVector<Value *, 8> CmpOperands;
320 SmallVector<Value *, 2> ConditionsToProcess;
321 CmpInst::Predicate Pred;
322 Value *Operand = II->getOperand(0);
323 if (m_c_And(m_Cmp(Pred, m_Value(), m_Value()),
324 m_Cmp(Pred, m_Value(), m_Value()))
325 .match(II->getOperand(0))) {
326 ConditionsToProcess.push_back(cast<BinaryOperator>(Operand)->getOperand(0));
327 ConditionsToProcess.push_back(cast<BinaryOperator>(Operand)->getOperand(1));
328 ConditionsToProcess.push_back(Operand);
329 } else if (isa<CmpInst>(Operand)) {
331 ConditionsToProcess.push_back(Operand);
333 for (auto Cond : ConditionsToProcess) {
334 if (auto *Cmp = dyn_cast<CmpInst>(Cond)) {
335 collectCmpOps(Cmp, CmpOperands);
336 // Now add our copy infos for our operands
337 for (auto *Op : CmpOperands) {
338 auto *PA = new PredicateAssume(Op, II, Cmp);
339 addInfoFor(OpsToRename, Op, PA);
342 } else if (auto *BinOp = dyn_cast<BinaryOperator>(Cond)) {
343 // Otherwise, it should be an AND.
344 assert(BinOp->getOpcode() == Instruction::And &&
345 "Should have been an AND");
346 auto *PA = new PredicateAssume(BinOp, II, BinOp);
347 addInfoFor(OpsToRename, BinOp, PA);
349 llvm_unreachable("Unknown type of condition");
354 // Process a block terminating branch, and place relevant operations to be
355 // renamed into OpsToRename.
356 void PredicateInfo::processBranch(BranchInst *BI, BasicBlock *BranchBB,
357 SmallPtrSetImpl<Value *> &OpsToRename) {
358 BasicBlock *FirstBB = BI->getSuccessor(0);
359 BasicBlock *SecondBB = BI->getSuccessor(1);
360 SmallVector<BasicBlock *, 2> SuccsToProcess;
361 SuccsToProcess.push_back(FirstBB);
362 SuccsToProcess.push_back(SecondBB);
363 SmallVector<Value *, 2> ConditionsToProcess;
365 auto InsertHelper = [&](Value *Op, bool isAnd, bool isOr, Value *Cond) {
366 for (auto *Succ : SuccsToProcess) {
367 // Don't try to insert on a self-edge. This is mainly because we will
368 // eliminate during renaming anyway.
369 if (Succ == BranchBB)
371 bool TakenEdge = (Succ == FirstBB);
372 // For and, only insert on the true edge
373 // For or, only insert on the false edge
374 if ((isAnd && !TakenEdge) || (isOr && TakenEdge))
377 new PredicateBranch(Op, BranchBB, Succ, Cond, TakenEdge);
378 addInfoFor(OpsToRename, Op, PB);
379 if (!Succ->getSinglePredecessor())
380 EdgeUsesOnly.insert({BranchBB, Succ});
384 // Match combinations of conditions.
385 CmpInst::Predicate Pred;
388 SmallVector<Value *, 8> CmpOperands;
389 if (match(BI->getCondition(), m_And(m_Cmp(Pred, m_Value(), m_Value()),
390 m_Cmp(Pred, m_Value(), m_Value()))) ||
391 match(BI->getCondition(), m_Or(m_Cmp(Pred, m_Value(), m_Value()),
392 m_Cmp(Pred, m_Value(), m_Value())))) {
393 auto *BinOp = cast<BinaryOperator>(BI->getCondition());
394 if (BinOp->getOpcode() == Instruction::And)
396 else if (BinOp->getOpcode() == Instruction::Or)
398 ConditionsToProcess.push_back(BinOp->getOperand(0));
399 ConditionsToProcess.push_back(BinOp->getOperand(1));
400 ConditionsToProcess.push_back(BI->getCondition());
401 } else if (isa<CmpInst>(BI->getCondition())) {
402 ConditionsToProcess.push_back(BI->getCondition());
404 for (auto Cond : ConditionsToProcess) {
405 if (auto *Cmp = dyn_cast<CmpInst>(Cond)) {
406 collectCmpOps(Cmp, CmpOperands);
407 // Now add our copy infos for our operands
408 for (auto *Op : CmpOperands)
409 InsertHelper(Op, isAnd, isOr, Cmp);
410 } else if (auto *BinOp = dyn_cast<BinaryOperator>(Cond)) {
411 // This must be an AND or an OR.
412 assert((BinOp->getOpcode() == Instruction::And ||
413 BinOp->getOpcode() == Instruction::Or) &&
414 "Should have been an AND or an OR");
415 // The actual value of the binop is not subject to the same restrictions
416 // as the comparison. It's either true or false on the true/false branch.
417 InsertHelper(BinOp, false, false, BinOp);
419 llvm_unreachable("Unknown type of condition");
424 // Process a block terminating switch, and place relevant operations to be
425 // renamed into OpsToRename.
426 void PredicateInfo::processSwitch(SwitchInst *SI, BasicBlock *BranchBB,
427 SmallPtrSetImpl<Value *> &OpsToRename) {
428 Value *Op = SI->getCondition();
429 if ((!isa<Instruction>(Op) && !isa<Argument>(Op)) || Op->hasOneUse())
432 // Remember how many outgoing edges there are to every successor.
433 SmallDenseMap<BasicBlock *, unsigned, 16> SwitchEdges;
434 for (unsigned i = 0, e = SI->getNumSuccessors(); i != e; ++i) {
435 BasicBlock *TargetBlock = SI->getSuccessor(i);
436 ++SwitchEdges[TargetBlock];
439 // Now propagate info for each case value
440 for (auto C : SI->cases()) {
441 BasicBlock *TargetBlock = C.getCaseSuccessor();
442 if (SwitchEdges.lookup(TargetBlock) == 1) {
443 PredicateSwitch *PS = new PredicateSwitch(
444 Op, SI->getParent(), TargetBlock, C.getCaseValue(), SI);
445 addInfoFor(OpsToRename, Op, PS);
446 if (!TargetBlock->getSinglePredecessor())
447 EdgeUsesOnly.insert({BranchBB, TargetBlock});
452 // Build predicate info for our function
453 void PredicateInfo::buildPredicateInfo() {
454 DT.updateDFSNumbers();
455 // Collect operands to rename from all conditional branch terminators, as well
456 // as assume statements.
457 SmallPtrSet<Value *, 8> OpsToRename;
458 for (auto DTN : depth_first(DT.getRootNode())) {
459 BasicBlock *BranchBB = DTN->getBlock();
460 if (auto *BI = dyn_cast<BranchInst>(BranchBB->getTerminator())) {
461 if (!BI->isConditional())
463 processBranch(BI, BranchBB, OpsToRename);
464 } else if (auto *SI = dyn_cast<SwitchInst>(BranchBB->getTerminator())) {
465 processSwitch(SI, BranchBB, OpsToRename);
468 for (auto &Assume : AC.assumptions()) {
469 if (auto *II = dyn_cast_or_null<IntrinsicInst>(Assume))
470 processAssume(II, II->getParent(), OpsToRename);
472 // Now rename all our operations.
473 renameUses(OpsToRename);
476 // Given the renaming stack, make all the operands currently on the stack real
477 // by inserting them into the IR. Return the last operation's value.
478 Value *PredicateInfo::materializeStack(unsigned int &Counter,
479 ValueDFSStack &RenameStack,
481 // Find the first thing we have to materialize
482 auto RevIter = RenameStack.rbegin();
483 for (; RevIter != RenameStack.rend(); ++RevIter)
487 size_t Start = RevIter - RenameStack.rbegin();
488 // The maximum number of things we should be trying to materialize at once
489 // right now is 4, depending on if we had an assume, a branch, and both used
490 // and of conditions.
491 for (auto RenameIter = RenameStack.end() - Start;
492 RenameIter != RenameStack.end(); ++RenameIter) {
494 RenameIter == RenameStack.begin() ? OrigOp : (RenameIter - 1)->Def;
495 ValueDFS &Result = *RenameIter;
496 auto *ValInfo = Result.PInfo;
497 // For edge predicates, we can just place the operand in the block before
498 // the terminator. For assume, we have to place it right before the assume
499 // to ensure we dominate all of our uses. Always insert right before the
500 // relevant instruction (terminator, assume), so that we insert in proper
501 // order in the case of multiple predicateinfo in the same block.
502 if (isa<PredicateWithEdge>(ValInfo)) {
503 IRBuilder<> B(getBranchTerminator(ValInfo));
504 Function *IF = Intrinsic::getDeclaration(
505 F.getParent(), Intrinsic::ssa_copy, Op->getType());
507 B.CreateCall(IF, Op, Op->getName() + "." + Twine(Counter++));
508 PredicateMap.insert({PIC, ValInfo});
511 auto *PAssume = dyn_cast<PredicateAssume>(ValInfo);
513 "Should not have gotten here without it being an assume");
514 IRBuilder<> B(PAssume->AssumeInst);
515 Function *IF = Intrinsic::getDeclaration(
516 F.getParent(), Intrinsic::ssa_copy, Op->getType());
517 CallInst *PIC = B.CreateCall(IF, Op);
518 PredicateMap.insert({PIC, ValInfo});
522 return RenameStack.back().Def;
525 // Instead of the standard SSA renaming algorithm, which is O(Number of
526 // instructions), and walks the entire dominator tree, we walk only the defs +
527 // uses. The standard SSA renaming algorithm does not really rely on the
528 // dominator tree except to order the stack push/pops of the renaming stacks, so
529 // that defs end up getting pushed before hitting the correct uses. This does
530 // not require the dominator tree, only the *order* of the dominator tree. The
531 // complete and correct ordering of the defs and uses, in dominator tree is
532 // contained in the DFS numbering of the dominator tree. So we sort the defs and
533 // uses into the DFS ordering, and then just use the renaming stack as per
534 // normal, pushing when we hit a def (which is a predicateinfo instruction),
535 // popping when we are out of the dfs scope for that def, and replacing any uses
536 // with top of stack if it exists. In order to handle liveness without
537 // propagating liveness info, we don't actually insert the predicateinfo
538 // instruction def until we see a use that it would dominate. Once we see such
539 // a use, we materialize the predicateinfo instruction in the right place and
542 // TODO: Use this algorithm to perform fast single-variable renaming in
543 // promotememtoreg and memoryssa.
544 void PredicateInfo::renameUses(SmallPtrSetImpl<Value *> &OpSet) {
545 // Sort OpsToRename since we are going to iterate it.
546 SmallVector<Value *, 8> OpsToRename(OpSet.begin(), OpSet.end());
547 std::sort(OpsToRename.begin(), OpsToRename.end(), [&](const Value *A,
549 auto *ArgA = dyn_cast_or_null<Argument>(A);
550 auto *ArgB = dyn_cast_or_null<Argument>(B);
552 // If A and B are args, order them based on their arg no.
558 return ArgA->getArgNo() < ArgB->getArgNo();
560 // Else, A are B are instructions.
561 // If they belong to different BBs, order them by the dominance of BBs.
562 auto *AInst = cast<Instruction>(A);
563 auto *BInst = cast<Instruction>(B);
564 if (AInst->getParent() != BInst->getParent())
565 return DT.dominates(AInst->getParent(), BInst->getParent());
567 // Else, A and B belong to the same BB.
568 // Order A and B by their dominance.
569 auto *BB = AInst->getParent();
570 auto LookupResult = OBBMap.find(BB);
571 if (LookupResult != OBBMap.end())
572 return LookupResult->second->dominates(AInst, BInst);
574 auto Result = OBBMap.insert({BB, make_unique<OrderedBasicBlock>(BB)});
575 return Result.first->second->dominates(AInst, BInst);
578 ValueDFS_Compare Compare(OBBMap);
579 // Compute liveness, and rename in O(uses) per Op.
580 for (auto *Op : OpsToRename) {
581 unsigned Counter = 0;
582 SmallVector<ValueDFS, 16> OrderedUses;
583 const auto &ValueInfo = getValueInfo(Op);
584 // Insert the possible copies into the def/use list.
585 // They will become real copies if we find a real use for them, and never
586 // created otherwise.
587 for (auto &PossibleCopy : ValueInfo.Infos) {
589 // Determine where we are going to place the copy by the copy type.
590 // The predicate info for branches always come first, they will get
591 // materialized in the split block at the top of the block.
592 // The predicate info for assumes will be somewhere in the middle,
593 // it will get materialized in front of the assume.
594 if (const auto *PAssume = dyn_cast<PredicateAssume>(PossibleCopy)) {
595 VD.LocalNum = LN_Middle;
596 DomTreeNode *DomNode = DT.getNode(PAssume->AssumeInst->getParent());
599 VD.DFSIn = DomNode->getDFSNumIn();
600 VD.DFSOut = DomNode->getDFSNumOut();
601 VD.PInfo = PossibleCopy;
602 OrderedUses.push_back(VD);
603 } else if (isa<PredicateWithEdge>(PossibleCopy)) {
604 // If we can only do phi uses, we treat it like it's in the branch
605 // block, and handle it specially. We know that it goes last, and only
606 // dominate phi uses.
607 auto BlockEdge = getBlockEdge(PossibleCopy);
608 if (EdgeUsesOnly.count(BlockEdge)) {
609 VD.LocalNum = LN_Last;
610 auto *DomNode = DT.getNode(BlockEdge.first);
612 VD.DFSIn = DomNode->getDFSNumIn();
613 VD.DFSOut = DomNode->getDFSNumOut();
614 VD.PInfo = PossibleCopy;
616 OrderedUses.push_back(VD);
619 // Otherwise, we are in the split block (even though we perform
620 // insertion in the branch block).
621 // Insert a possible copy at the split block and before the branch.
622 VD.LocalNum = LN_First;
623 auto *DomNode = DT.getNode(BlockEdge.second);
625 VD.DFSIn = DomNode->getDFSNumIn();
626 VD.DFSOut = DomNode->getDFSNumOut();
627 VD.PInfo = PossibleCopy;
628 OrderedUses.push_back(VD);
634 convertUsesToDFSOrdered(Op, OrderedUses);
635 std::sort(OrderedUses.begin(), OrderedUses.end(), Compare);
636 SmallVector<ValueDFS, 8> RenameStack;
637 // For each use, sorted into dfs order, push values and replaces uses with
638 // top of stack, which will represent the reaching def.
639 for (auto &VD : OrderedUses) {
640 // We currently do not materialize copy over copy, but we should decide if
642 bool PossibleCopy = VD.PInfo != nullptr;
643 if (RenameStack.empty()) {
644 DEBUG(dbgs() << "Rename Stack is empty\n");
646 DEBUG(dbgs() << "Rename Stack Top DFS numbers are ("
647 << RenameStack.back().DFSIn << ","
648 << RenameStack.back().DFSOut << ")\n");
651 DEBUG(dbgs() << "Current DFS numbers are (" << VD.DFSIn << ","
652 << VD.DFSOut << ")\n");
654 bool ShouldPush = (VD.Def || PossibleCopy);
655 bool OutOfScope = !stackIsInScope(RenameStack, VD);
656 if (OutOfScope || ShouldPush) {
657 // Sync to our current scope.
658 popStackUntilDFSScope(RenameStack, VD);
660 RenameStack.push_back(VD);
663 // If we get to this point, and the stack is empty we must have a use
664 // with no renaming needed, just skip it.
665 if (RenameStack.empty())
667 // Skip values, only want to rename the uses
668 if (VD.Def || PossibleCopy)
670 if (!DebugCounter::shouldExecute(RenameCounter)) {
671 DEBUG(dbgs() << "Skipping execution due to debug counter\n");
674 ValueDFS &Result = RenameStack.back();
676 // If the possible copy dominates something, materialize our stack up to
677 // this point. This ensures every comparison that affects our operation
678 // ends up with predicateinfo.
680 Result.Def = materializeStack(Counter, RenameStack, Op);
682 DEBUG(dbgs() << "Found replacement " << *Result.Def << " for "
683 << *VD.U->get() << " in " << *(VD.U->getUser()) << "\n");
684 assert(DT.dominates(cast<Instruction>(Result.Def), *VD.U) &&
685 "Predicateinfo def should have dominated this use");
686 VD.U->set(Result.Def);
691 PredicateInfo::ValueInfo &PredicateInfo::getOrCreateValueInfo(Value *Operand) {
692 auto OIN = ValueInfoNums.find(Operand);
693 if (OIN == ValueInfoNums.end()) {
695 ValueInfos.resize(ValueInfos.size() + 1);
696 // This will use the new size and give us a 0 based number of the info
697 auto InsertResult = ValueInfoNums.insert({Operand, ValueInfos.size() - 1});
698 assert(InsertResult.second && "Value info number already existed?");
699 return ValueInfos[InsertResult.first->second];
701 return ValueInfos[OIN->second];
704 const PredicateInfo::ValueInfo &
705 PredicateInfo::getValueInfo(Value *Operand) const {
706 auto OINI = ValueInfoNums.lookup(Operand);
707 assert(OINI != 0 && "Operand was not really in the Value Info Numbers");
708 assert(OINI < ValueInfos.size() &&
709 "Value Info Number greater than size of Value Info Table");
710 return ValueInfos[OINI];
713 PredicateInfo::PredicateInfo(Function &F, DominatorTree &DT,
715 : F(F), DT(DT), AC(AC) {
716 // Push an empty operand info so that we can detect 0 as not finding one
717 ValueInfos.resize(1);
718 buildPredicateInfo();
721 PredicateInfo::~PredicateInfo() {}
723 void PredicateInfo::verifyPredicateInfo() const {}
725 char PredicateInfoPrinterLegacyPass::ID = 0;
727 PredicateInfoPrinterLegacyPass::PredicateInfoPrinterLegacyPass()
729 initializePredicateInfoPrinterLegacyPassPass(
730 *PassRegistry::getPassRegistry());
733 void PredicateInfoPrinterLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
734 AU.setPreservesAll();
735 AU.addRequiredTransitive<DominatorTreeWrapperPass>();
736 AU.addRequired<AssumptionCacheTracker>();
739 bool PredicateInfoPrinterLegacyPass::runOnFunction(Function &F) {
740 auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
741 auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
742 auto PredInfo = make_unique<PredicateInfo>(F, DT, AC);
743 PredInfo->print(dbgs());
744 if (VerifyPredicateInfo)
745 PredInfo->verifyPredicateInfo();
749 PreservedAnalyses PredicateInfoPrinterPass::run(Function &F,
750 FunctionAnalysisManager &AM) {
751 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
752 auto &AC = AM.getResult<AssumptionAnalysis>(F);
753 OS << "PredicateInfo for function: " << F.getName() << "\n";
754 make_unique<PredicateInfo>(F, DT, AC)->print(OS);
756 return PreservedAnalyses::all();
759 /// \brief An assembly annotator class to print PredicateInfo information in
761 class PredicateInfoAnnotatedWriter : public AssemblyAnnotationWriter {
762 friend class PredicateInfo;
763 const PredicateInfo *PredInfo;
766 PredicateInfoAnnotatedWriter(const PredicateInfo *M) : PredInfo(M) {}
768 virtual void emitBasicBlockStartAnnot(const BasicBlock *BB,
769 formatted_raw_ostream &OS) {}
771 virtual void emitInstructionAnnot(const Instruction *I,
772 formatted_raw_ostream &OS) {
773 if (const auto *PI = PredInfo->getPredicateInfoFor(I)) {
774 OS << "; Has predicate info\n";
775 if (const auto *PB = dyn_cast<PredicateBranch>(PI)) {
776 OS << "; branch predicate info { TrueEdge: " << PB->TrueEdge
777 << " Comparison:" << *PB->Condition << " Edge: [";
778 PB->From->printAsOperand(OS);
780 PB->To->printAsOperand(OS);
782 } else if (const auto *PS = dyn_cast<PredicateSwitch>(PI)) {
783 OS << "; switch predicate info { CaseValue: " << *PS->CaseValue
784 << " Switch:" << *PS->Switch << " Edge: [";
785 PS->From->printAsOperand(OS);
787 PS->To->printAsOperand(OS);
789 } else if (const auto *PA = dyn_cast<PredicateAssume>(PI)) {
790 OS << "; assume predicate info {"
791 << " Comparison:" << *PA->Condition << " }\n";
797 void PredicateInfo::print(raw_ostream &OS) const {
798 PredicateInfoAnnotatedWriter Writer(this);
799 F.print(OS, &Writer);
802 void PredicateInfo::dump() const {
803 PredicateInfoAnnotatedWriter Writer(this);
804 F.print(dbgs(), &Writer);
807 PreservedAnalyses PredicateInfoVerifierPass::run(Function &F,
808 FunctionAnalysisManager &AM) {
809 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
810 auto &AC = AM.getResult<AssumptionAnalysis>(F);
811 make_unique<PredicateInfo>(F, DT, AC)->verifyPredicateInfo();
813 return PreservedAnalyses::all();