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Revert previous patch, appears to break bootstrap.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61181 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2008-12-18 01:23:41 +00:00
parent a32b7ac86f
commit a1d9cb1d46
1 changed files with 29 additions and 88 deletions
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117
lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@ -508,22 +508,14 @@ bool LoopStrengthReduce::AddUsersIfInteresting(Instruction *I, Loop *L,
if (isa<PHINode>(User) && Processed.count(User))
continue;
// Descend recursively, but not into PHI nodes outside the current loop.
// It's important to see the entire expression outside the loop to get
// choices that depend on addressing mode use right, although we won't
// consider references ouside the loop in all cases.
// 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.
// If this is an instruction defined in a nested loop, or outside this loop,
// don't recurse into it.
bool AddUserToIVUsers = false;
if (LI->getLoopFor(User->getParent()) != L) {
if (isa<PHINode>(User) || Processed.count(User) ||
!AddUsersIfInteresting(User, L, Processed)) {
DOUT << "FOUND USER in other loop: " << *User
<< " OF SCEV: " << *ISE << "\n";
AddUserToIVUsers = true;
}
} else if (Processed.count(User) ||
!AddUsersIfInteresting(User, L, Processed)) {
DOUT << "FOUND USER in other loop: " << *User
<< " OF SCEV: " << *ISE << "\n";
AddUserToIVUsers = true;
} else if (!AddUsersIfInteresting(User, L, Processed)) {
DOUT << "FOUND USER: " << *User
<< " OF SCEV: " << *ISE << "\n";
AddUserToIVUsers = true;
@ -712,45 +704,34 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
PHINode *PN = cast<PHINode>(Inst);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
if (PN->getIncomingValue(i) == OperandValToReplace) {
// If the original expression is outside the loop, put the replacement
// code in the same place as the original expression,
// which need not be an immediate predecessor of this PHI. This way we
// need only one copy of it even if it is referenced multiple times in
// the PHI. We don't do this when the original expression is inside the
// loop because multiple copies sometimes do useful sinking of code in that
// case(?).
Instruction *OldLoc = dyn_cast<Instruction>(OperandValToReplace);
if (L->contains(OldLoc->getParent())) {
// If this is a critical edge, split the edge so that we do not insert the
// code on all predecessor/successor paths. We do this unless this is the
// canonical backedge for this loop, as this can make some inserted code
// be in an illegal position.
BasicBlock *PHIPred = PN->getIncomingBlock(i);
if (e != 1 && PHIPred->getTerminator()->getNumSuccessors() > 1 &&
(PN->getParent() != L->getHeader() || !L->contains(PHIPred))) {
// First step, split the critical edge.
SplitCriticalEdge(PHIPred, PN->getParent(), P, false);
// Next step: move the basic block. In particular, if the PHI node
// is outside of the loop, and PredTI is in the loop, we want to
// move the block to be immediately before the PHI block, not
// immediately after PredTI.
if (L->contains(PHIPred) && !L->contains(PN->getParent())) {
BasicBlock *NewBB = PN->getIncomingBlock(i);
NewBB->moveBefore(PN->getParent());
}
// Splitting the edge can reduce the number of PHI entries we have.
e = PN->getNumIncomingValues();
// If this is a critical edge, split the edge so that we do not insert the
// code on all predecessor/successor paths. We do this unless this is the
// canonical backedge for this loop, as this can make some inserted code
// be in an illegal position.
BasicBlock *PHIPred = PN->getIncomingBlock(i);
if (e != 1 && PHIPred->getTerminator()->getNumSuccessors() > 1 &&
(PN->getParent() != L->getHeader() || !L->contains(PHIPred))) {
// First step, split the critical edge.
SplitCriticalEdge(PHIPred, PN->getParent(), P, false);
// Next step: move the basic block. In particular, if the PHI node
// is outside of the loop, and PredTI is in the loop, we want to
// move the block to be immediately before the PHI block, not
// immediately after PredTI.
if (L->contains(PHIPred) && !L->contains(PN->getParent())) {
BasicBlock *NewBB = PN->getIncomingBlock(i);
NewBB->moveBefore(PN->getParent());
}
// Splitting the edge can reduce the number of PHI entries we have.
e = PN->getNumIncomingValues();
}
Value *&Code = InsertedCode[PN->getIncomingBlock(i)];
if (!Code) {
// Insert the code into the end of the predecessor block.
Instruction *InsertPt = (L->contains(OldLoc->getParent())) ?
PN->getIncomingBlock(i)->getTerminator() :
OldLoc->getParent()->getTerminator();
Instruction *InsertPt = PN->getIncomingBlock(i)->getTerminator();
Code = InsertCodeForBaseAtPosition(NewBase, Rewriter, InsertPt, L);
// Adjust the type back to match the PHI. Note that we can't use
@ -1187,10 +1168,6 @@ bool LoopStrengthReduce::RequiresTypeConversion(const Type *Ty1,
/// mode scale component and optional base reg. This allows the users of
/// this stride to be rewritten as prev iv * factor. It returns 0 if no
/// reuse is possible. Factors can be negative on same targets, e.g. ARM.
///
/// If all uses are outside the loop, we don't require that all multiplies
/// be folded into the addressing mode; a multiply (executed once) outside
/// the loop is better than another IV within. Well, usually.
int64_t LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg,
bool AllUsesAreAddresses,
bool AllUsesAreOutsideLoop,
@ -1228,30 +1205,6 @@ int64_t LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg,
return Scale;
}
}
} else if (AllUsesAreOutsideLoop) {
// Accept nonconstant strides here; it is really really right to substitute
// an existing IV if we can.
// Special case, old IV is -1*x and this one is x. Can treat this one as
// -1*old.
for (unsigned NewStride = 0, e = StrideOrder.size(); NewStride != e;
++NewStride) {
std::map<SCEVHandle, IVsOfOneStride>::iterator SI =
IVsByStride.find(StrideOrder[NewStride]);
if (SI == IVsByStride.end())
continue;
if (SCEVMulExpr *ME = dyn_cast<SCEVMulExpr>(SI->first))
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(ME->getOperand(0)))
if (Stride == ME->getOperand(1) &&
SC->getValue()->getSExtValue() == -1LL)
for (std::vector<IVExpr>::iterator II = SI->second.IVs.begin(),
IE = SI->second.IVs.end(); II != IE; ++II)
// Accept nonzero base here.
// Only reuse previous IV if it would not require a type conversion.
if (!RequiresTypeConversion(II->Base->getType(), Ty)) {
IV = *II;
return -1;
}
}
}
return 0;
}
@ -1596,18 +1549,6 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
!cast<ConstantInt>(CommonBaseV)->isZero())
RewriteExpr = SE->getAddExpr(RewriteExpr,
SE->getUnknown(CommonBaseV));
// If we're reusing an IV with a nonzero base (currently this happens
// only when all reuses are outside the loop) subtract out that base here
// This is the reverse of the above; the base HAS been used to initialize
// the PHI node but we don't want it here.
// (If the RewriteFactor is negative, we're effectively negating the
// old IV in this use, so we add the base instead of subtract.)
if (!ReuseIV.Base->isZero()) {
if (RewriteFactor < 0)
RewriteExpr = SE->getAddExpr(RewriteExpr, ReuseIV.Base);
else
RewriteExpr = SE->getMinusSCEV(RewriteExpr, ReuseIV.Base);
}
}
// Now that we know what we need to do, insert code before User for the