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Reapply LoopStrengthReduce and IVUsers cleanups, excluding the part

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of 91296 that caused trouble -- the Processed list needs to be
preserved for the livetime of the pass, as AddUsersIfInteresting
is called from other passes.

llvm-svn: 91641
This commit is contained in:
Dan Gohman 2009-12-18 00:06:20 +00:00
parent 06b6feb2e1
commit c483bed5e8
4 changed files with 34 additions and 80 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/llvm/Analysis/IVUsers.h
View File

@ -175,11 +175,11 @@ class IVUsers : public LoopPass {
ScalarEvolution *SE;
SmallPtrSet<Instruction*,16> Processed;
public:
/// IVUses - A list of all tracked IV uses of induction variable expressions
/// we are interested in.
ilist<IVUsersOfOneStride> IVUses;
public:
/// IVUsesByStride - A mapping from the strides in StrideOrder to the
/// uses in IVUses.
std::map<const SCEV *, IVUsersOfOneStride*> IVUsesByStride;

7
include/llvm/Analysis/LoopInfo.h
View File

@ -976,13 +976,6 @@ public:
void removeBlock(BasicBlock *BB) {
LI.removeBlock(BB);
}
static bool isNotAlreadyContainedIn(const Loop *SubLoop,
const Loop *ParentLoop) {
return
LoopInfoBase<BasicBlock, Loop>::isNotAlreadyContainedIn(SubLoop,
ParentLoop);
}
};

3
lib/Analysis/IVUsers.cpp
View File

@ -53,7 +53,7 @@ static bool containsAddRecFromDifferentLoop(const SCEV *S, Loop *L) {
if (newLoop == L)
return false;
// if newLoop is an outer loop of L, this is OK.
if (!LoopInfo::isNotAlreadyContainedIn(L, newLoop))
if (newLoop->contains(L->getHeader()))
return false;
}
return true;
@ -370,6 +370,7 @@ void IVUsers::releaseMemory() {
IVUsesByStride.clear();
StrideOrder.clear();
Processed.clear();
IVUses.clear();
}
void IVStrideUse::deleted() {

102
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -24,18 +24,14 @@
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Type.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/IVUsers.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Transforms/Utils/AddrModeMatcher.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ValueHandle.h"
@ -85,8 +81,6 @@ namespace {
class LoopStrengthReduce : public LoopPass {
IVUsers *IU;
LoopInfo *LI;
DominatorTree *DT;
ScalarEvolution *SE;
bool Changed;
@ -94,10 +88,6 @@ namespace {
/// particular stride.
std::map<const SCEV *, IVsOfOneStride> IVsByStride;
/// StrideNoReuse - Keep track of all the strides whose ivs cannot be
/// reused (nor should they be rewritten to reuse other strides).
SmallSet<const SCEV *, 4> StrideNoReuse;
/// DeadInsts - Keep track of instructions we may have made dead, so that
/// we can remove them after we are done working.
SmallVector<WeakVH, 16> DeadInsts;
@ -109,8 +99,7 @@ namespace {
public:
static char ID; // Pass ID, replacement for typeid
explicit LoopStrengthReduce(const TargetLowering *tli = NULL) :
LoopPass(&ID), TLI(tli) {
}
LoopPass(&ID), TLI(tli) {}
bool runOnLoop(Loop *L, LPPassManager &LPM);
@ -118,13 +107,11 @@ namespace {
// We split critical edges, so we change the CFG. However, we do update
// many analyses if they are around.
AU.addPreservedID(LoopSimplifyID);
AU.addPreserved<LoopInfo>();
AU.addPreserved<DominanceFrontier>();
AU.addPreserved<DominatorTree>();
AU.addPreserved("loops");
AU.addPreserved("domfrontier");
AU.addPreserved("domtree");
AU.addRequiredID(LoopSimplifyID);
AU.addRequired<LoopInfo>();
AU.addRequired<DominatorTree>();
AU.addRequired<ScalarEvolution>();
AU.addPreserved<ScalarEvolution>();
AU.addRequired<IVUsers>();
@ -228,19 +215,17 @@ void LoopStrengthReduce::DeleteTriviallyDeadInstructions() {
if (DeadInsts.empty()) return;
while (!DeadInsts.empty()) {
Instruction *I = dyn_cast_or_null<Instruction>(DeadInsts.back());
DeadInsts.pop_back();
Instruction *I = dyn_cast_or_null<Instruction>(DeadInsts.pop_back_val());
if (I == 0 || !isInstructionTriviallyDead(I))
continue;
for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI) {
for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI)
if (Instruction *U = dyn_cast<Instruction>(*OI)) {
*OI = 0;
if (U->use_empty())
DeadInsts.push_back(U);
}
}
I->eraseFromParent();
Changed = true;
@ -300,9 +285,6 @@ namespace {
/// BasedUser - For a particular base value, keep information about how we've
/// partitioned the expression so far.
struct BasedUser {
/// SE - The current ScalarEvolution object.
ScalarEvolution *SE;
/// Base - The Base value for the PHI node that needs to be inserted for
/// this use. As the use is processed, information gets moved from this
/// field to the Imm field (below). BasedUser values are sorted by this
@ -334,9 +316,9 @@ namespace {
bool isUseOfPostIncrementedValue;
BasedUser(IVStrideUse &IVSU, ScalarEvolution *se)
: SE(se), Base(IVSU.getOffset()), Inst(IVSU.getUser()),
: Base(IVSU.getOffset()), Inst(IVSU.getUser()),
OperandValToReplace(IVSU.getOperandValToReplace()),
Imm(SE->getIntegerSCEV(0, Base->getType())),
Imm(se->getIntegerSCEV(0, Base->getType())),
isUseOfPostIncrementedValue(IVSU.isUseOfPostIncrementedValue()) {}
// Once we rewrite the code to insert the new IVs we want, update the
@ -345,14 +327,14 @@ namespace {
void RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
Instruction *InsertPt,
SCEVExpander &Rewriter, Loop *L, Pass *P,
LoopInfo &LI,
SmallVectorImpl<WeakVH> &DeadInsts);
SmallVectorImpl<WeakVH> &DeadInsts,
ScalarEvolution *SE);
Value *InsertCodeForBaseAtPosition(const SCEV *const &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L,
LoopInfo &LI);
Instruction *IP,
ScalarEvolution *SE);
void dump() const;
};
}
@ -366,27 +348,12 @@ void BasedUser::dump() const {
Value *BasedUser::InsertCodeForBaseAtPosition(const SCEV *const &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L,
LoopInfo &LI) {
// Figure out where we *really* want to insert this code. In particular, if
// the user is inside of a loop that is nested inside of L, we really don't
// want to insert this expression before the user, we'd rather pull it out as
// many loops as possible.
Instruction *BaseInsertPt = IP;
// Figure out the most-nested loop that IP is in.
Loop *InsertLoop = LI.getLoopFor(IP->getParent());
// If InsertLoop is not L, and InsertLoop is nested inside of L, figure out
// the preheader of the outer-most loop where NewBase is not loop invariant.
if (L->contains(IP->getParent()))
while (InsertLoop && NewBase->isLoopInvariant(InsertLoop)) {
BaseInsertPt = InsertLoop->getLoopPreheader()->getTerminator();
InsertLoop = InsertLoop->getParentLoop();
}
Value *Base = Rewriter.expandCodeFor(NewBase, 0, BaseInsertPt);
Instruction *IP,
ScalarEvolution *SE) {
Value *Base = Rewriter.expandCodeFor(NewBase, 0, IP);
// Wrap the base in a SCEVUnknown so that ScalarEvolution doesn't try to
// re-analyze it.
const SCEV *NewValSCEV = SE->getUnknown(Base);
// Always emit the immediate into the same block as the user.
@ -405,8 +372,8 @@ Value *BasedUser::InsertCodeForBaseAtPosition(const SCEV *const &NewBase,
void BasedUser::RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
Instruction *NewBasePt,
SCEVExpander &Rewriter, Loop *L, Pass *P,
LoopInfo &LI,
SmallVectorImpl<WeakVH> &DeadInsts) {
SmallVectorImpl<WeakVH> &DeadInsts,
ScalarEvolution *SE) {
if (!isa<PHINode>(Inst)) {
// By default, insert code at the user instruction.
BasicBlock::iterator InsertPt = Inst;
@ -435,7 +402,7 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
}
Value *NewVal = InsertCodeForBaseAtPosition(NewBase,
OperandValToReplace->getType(),
Rewriter, InsertPt, L, LI);
Rewriter, InsertPt, SE);
// Replace the use of the operand Value with the new Phi we just created.
Inst->replaceUsesOfWith(OperandValToReplace, NewVal);
@ -497,7 +464,7 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
PHIPred->getTerminator() :
OldLoc->getParent()->getTerminator();
Code = InsertCodeForBaseAtPosition(NewBase, PN->getType(),
Rewriter, InsertPt, L, LI);
Rewriter, InsertPt, SE);
DEBUG(errs() << " Changing PHI use to ");
DEBUG(WriteAsOperand(errs(), Code, /*PrintType=*/false));
@ -973,17 +940,13 @@ const SCEV *LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg,
const SCEV *const &Stride,
IVExpr &IV, const Type *Ty,
const std::vector<BasedUser>& UsersToProcess) {
if (StrideNoReuse.count(Stride))
return SE->getIntegerSCEV(0, Stride->getType());
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Stride)) {
int64_t SInt = SC->getValue()->getSExtValue();
for (unsigned NewStride = 0, e = IU->StrideOrder.size();
NewStride != e; ++NewStride) {
std::map<const SCEV *, IVsOfOneStride>::iterator SI =
IVsByStride.find(IU->StrideOrder[NewStride]);
if (SI == IVsByStride.end() || !isa<SCEVConstant>(SI->first) ||
StrideNoReuse.count(SI->first))
if (SI == IVsByStride.end() || !isa<SCEVConstant>(SI->first))
continue;
// The other stride has no uses, don't reuse it.
std::map<const SCEV *, IVUsersOfOneStride *>::iterator UI =
@ -1742,8 +1705,8 @@ LoopStrengthReduce::StrengthReduceIVUsersOfStride(const SCEV *const &Stride,
RewriteExpr = SE->getAddExpr(RewriteExpr, SE->getUnknown(BaseV));
User.RewriteInstructionToUseNewBase(RewriteExpr, NewBasePt,
Rewriter, L, this, *LI,
DeadInsts);
Rewriter, L, this,
DeadInsts, SE);
// Mark old value we replaced as possibly dead, so that it is eliminated
// if we just replaced the last use of that value.
@ -2707,8 +2670,6 @@ bool LoopStrengthReduce::OptimizeLoopCountIV(Loop *L) {
bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager &LPM) {
IU = &getAnalysis<IVUsers>();
LI = &getAnalysis<LoopInfo>();
DT = &getAnalysis<DominatorTree>();
SE = &getAnalysis<ScalarEvolution>();
Changed = false;
@ -2754,16 +2715,15 @@ bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager &LPM) {
// After all sharing is done, see if we can adjust the loop to test against
// zero instead of counting up to a maximum. This is usually faster.
OptimizeLoopCountIV(L);
// We're done analyzing this loop; release all the state we built up for it.
IVsByStride.clear();
// Clean up after ourselves
if (!DeadInsts.empty())
DeleteTriviallyDeadInstructions();
}
// We're done analyzing this loop; release all the state we built up for it.
IVsByStride.clear();
StrideNoReuse.clear();
// Clean up after ourselves
if (!DeadInsts.empty())
DeleteTriviallyDeadInstructions();
// At this point, it is worth checking to see if any recurrence PHIs are also
// dead, so that we can remove them as well.
DeleteDeadPHIs(L->getHeader());