#define DEBUG_TYPE "iv-users"
#include "llvm/Analysis/IVUsers.h"
-#include "llvm/Constants.h"
-#include "llvm/Instructions.h"
-#include "llvm/Type.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Analysis/Dominators.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Assembly/Writer.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
INITIALIZE_PASS_BEGIN(IVUsers, "iv-users",
"Induction Variable Users", false, true)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
-INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
INITIALIZE_PASS_END(IVUsers, "iv-users",
"Induction Variable Users", false, true)
return false;
}
-/// Return true if this loop and all loop headers that dominate it are in
-/// simplified form.
-static bool isSimplifiedLoopNest(Loop *L, const DominatorTree *DT,
- const LoopInfo *LI) {
- if (!L->isLoopSimplifyForm())
- return false;
-
- for (DomTreeNode *Rung = DT->getNode(L->getLoopPreheader());
+/// Return true if all loop headers that dominate this block are in simplified
+/// form.
+static bool isSimplifiedLoopNest(BasicBlock *BB, const DominatorTree *DT,
+ const LoopInfo *LI,
+ SmallPtrSet<Loop*,16> &SimpleLoopNests) {
+ Loop *NearestLoop = 0;
+ for (DomTreeNode *Rung = DT->getNode(BB);
Rung; Rung = Rung->getIDom()) {
- BasicBlock *BB = Rung->getBlock();
- const Loop *DomLoop = LI->getLoopFor(BB);
- if (DomLoop && DomLoop->getHeader() == BB) {
+ BasicBlock *DomBB = Rung->getBlock();
+ Loop *DomLoop = LI->getLoopFor(DomBB);
+ if (DomLoop && DomLoop->getHeader() == DomBB) {
+ // If the domtree walk reaches a loop with no preheader, return false.
if (!DomLoop->isLoopSimplifyForm())
return false;
+ // If we have already checked this loop nest, stop checking.
+ if (SimpleLoopNests.count(DomLoop))
+ break;
+ // If we have not already checked this loop nest, remember the loop
+ // header nearest to BB. The nearest loop may not contain BB.
+ if (!NearestLoop)
+ NearestLoop = DomLoop;
}
}
+ if (NearestLoop)
+ SimpleLoopNests.insert(NearestLoop);
return true;
}
-/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
+/// AddUsersImpl - Inspect the specified instruction. If it is a
/// reducible SCEV, recursively add its users to the IVUsesByStride set and
/// return true. Otherwise, return false.
-bool IVUsers::AddUsersIfInteresting(Instruction *I,
- SmallPtrSet<Loop*,16> &SimpleLoopNests) {
+bool IVUsers::AddUsersImpl(Instruction *I,
+ SmallPtrSet<Loop*,16> &SimpleLoopNests) {
// Add this IV user to the Processed set before returning false to ensure that
// all IV users are members of the set. See IVUsers::isIVUserOrOperand.
if (!Processed.insert(I))
if (!SE->isSCEVable(I->getType()))
return false; // Void and FP expressions cannot be reduced.
+ // IVUsers is used by LSR which assumes that all SCEV expressions are safe to
+ // pass to SCEVExpander. Expressions are not safe to expand if they represent
+ // operations that are not safe to speculate, namely integer division.
+ if (!isa<PHINode>(I) && !isSafeToSpeculativelyExecute(I, DL))
+ return false;
+
// LSR is not APInt clean, do not touch integers bigger than 64-bits.
// Also avoid creating IVs of non-native types. For example, we don't want a
// 64-bit IV in 32-bit code just because the loop has one 64-bit cast.
uint64_t Width = SE->getTypeSizeInBits(I->getType());
- if (Width > 64 || (TD && !TD->isLegalInteger(Width)))
+ if (Width > 64 || (DL && !DL->isLegalInteger(Width)))
return false;
// Get the symbolic expression for this instruction.
if (isa<PHINode>(User) && Processed.count(User))
continue;
- Loop *UserLoop = LI->getLoopFor(User->getParent());
-
// Only consider IVUsers that are dominated by simplified loop
// headers. Otherwise, SCEVExpander will crash.
- if (UserLoop && !SimpleLoopNests.count(UserLoop)) {
- if (!isSimplifiedLoopNest(UserLoop, DT, LI))
- return false;
- SimpleLoopNests.insert(UserLoop);
+ BasicBlock *UseBB = User->getParent();
+ // A phi's use is live out of its predecessor block.
+ if (PHINode *PHI = dyn_cast<PHINode>(User)) {
+ unsigned OperandNo = UI.getOperandNo();
+ unsigned ValNo = PHINode::getIncomingValueNumForOperand(OperandNo);
+ UseBB = PHI->getIncomingBlock(ValNo);
}
+ if (!isSimplifiedLoopNest(UseBB, DT, LI, SimpleLoopNests))
+ return false;
// Descend recursively, but not into PHI nodes outside the current loop.
// It's important to see the entire expression outside the loop to get
// If User is already in Processed, we don't want to recurse into it again,
// but do want to record a second reference in the same instruction.
bool AddUserToIVUsers = false;
- if (UserLoop != L) {
+ if (LI->getLoopFor(User->getParent()) != L) {
if (isa<PHINode>(User) || Processed.count(User) ||
- !AddUsersIfInteresting(User, SimpleLoopNests)) {
+ !AddUsersImpl(User, SimpleLoopNests)) {
DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n'
<< " OF SCEV: " << *ISE << '\n');
AddUserToIVUsers = true;
}
- } else if (Processed.count(User)
- || !AddUsersIfInteresting(User, SimpleLoopNests)) {
+ } else if (Processed.count(User) || !AddUsersImpl(User, SimpleLoopNests)) {
DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
<< " OF SCEV: " << *ISE << '\n');
AddUserToIVUsers = true;
return true;
}
+bool IVUsers::AddUsersIfInteresting(Instruction *I) {
+ // SCEVExpander can only handle users that are dominated by simplified loop
+ // entries. Keep track of all loops that are only dominated by other simple
+ // loops so we don't traverse the domtree for each user.
+ SmallPtrSet<Loop*,16> SimpleLoopNests;
+
+ return AddUsersImpl(I, SimpleLoopNests);
+}
+
IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) {
IVUses.push_back(new IVStrideUse(this, User, Operand));
return IVUses.back();
void IVUsers::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfo>();
- AU.addRequired<DominatorTree>();
+ AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<ScalarEvolution>();
AU.setPreservesAll();
}
L = l;
LI = &getAnalysis<LoopInfo>();
- DT = &getAnalysis<DominatorTree>();
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
SE = &getAnalysis<ScalarEvolution>();
- TD = getAnalysisIfAvailable<TargetData>();
-
- // SCEVExpander can only handle users that are dominated by simplified loop
- // entries. Keep track of all loops that are only dominated by other simple
- // loops so we don't traverse the domtree for each user.
- SmallPtrSet<Loop*,16> SimpleLoopNests;
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ DL = DLP ? &DLP->getDataLayout() : 0;
// Find all uses of induction variables in this loop, and categorize
// them by stride. Start by finding all of the PHI nodes in the header for
// this loop. If they are induction variables, inspect their uses.
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
- (void)AddUsersIfInteresting(I, SimpleLoopNests);
+ (void)AddUsersIfInteresting(I);
return false;
}
void IVUsers::print(raw_ostream &OS, const Module *M) const {
OS << "IV Users for loop ";
- WriteAsOperand(OS, L->getHeader(), false);
+ L->getHeader()->printAsOperand(OS, false);
if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
OS << " with backedge-taken count "
<< *SE->getBackedgeTakenCount(L);
for (ilist<IVStrideUse>::const_iterator UI = IVUses.begin(),
E = IVUses.end(); UI != E; ++UI) {
OS << " ";
- WriteAsOperand(OS, UI->getOperandValToReplace(), false);
+ UI->getOperandValToReplace()->printAsOperand(OS, false);
OS << " = " << *getReplacementExpr(*UI);
for (PostIncLoopSet::const_iterator
I = UI->PostIncLoops.begin(),
E = UI->PostIncLoops.end(); I != E; ++I) {
OS << " (post-inc with loop ";
- WriteAsOperand(OS, (*I)->getHeader(), false);
+ (*I)->getHeader()->printAsOperand(OS, false);
OS << ")";
}
OS << " in ";
}
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void IVUsers::dump() const {
print(dbgs());
}
+#endif
void IVUsers::releaseMemory() {
Processed.clear();
projects / oota-llvm.git / blobdiff