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Remove the code in LSR that manually hoists expansions out of loops; 

SCEVExpander does this automatically.

llvm-svn: 91281
This commit is contained in:
Dan Gohman 2009-12-14 16:52:55 +00:00
parent ec2a7c58e8
commit c3513095cf
1 changed files with 9 additions and 29 deletions
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38
llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@ -109,8 +109,7 @@ 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);
@ -381,14 +380,12 @@ namespace {
void RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
Instruction *InsertPt,
SCEVExpander &Rewriter, Loop *L, Pass *P,
LoopInfo &LI,
SmallVectorImpl<WeakVH> &DeadInsts);
Value *InsertCodeForBaseAtPosition(const SCEV *const &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L,
LoopInfo &LI);
Instruction *IP);
void dump() const;
};
}
@ -402,27 +399,11 @@ 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) {
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.
@ -441,7 +422,6 @@ 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) {
if (!isa<PHINode>(Inst)) {
// By default, insert code at the user instruction.
@ -471,7 +451,7 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
}
Value *NewVal = InsertCodeForBaseAtPosition(NewBase,
OperandValToReplace->getType(),
Rewriter, InsertPt, L, LI);
Rewriter, InsertPt);
// Replace the use of the operand Value with the new Phi we just created.
Inst->replaceUsesOfWith(OperandValToReplace, NewVal);
@ -533,7 +513,7 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
PHIPred->getTerminator() :
OldLoc->getParent()->getTerminator();
Code = InsertCodeForBaseAtPosition(NewBase, PN->getType(),
Rewriter, InsertPt, L, LI);
Rewriter, InsertPt);
DEBUG(errs() << " Changing PHI use to ");
DEBUG(WriteAsOperand(errs(), Code, /*PrintType=*/false));
@ -1778,7 +1758,7 @@ LoopStrengthReduce::StrengthReduceIVUsersOfStride(const SCEV *const &Stride,
RewriteExpr = SE->getAddExpr(RewriteExpr, SE->getUnknown(BaseV));
User.RewriteInstructionToUseNewBase(RewriteExpr, NewBasePt,
Rewriter, L, this, *LI,
Rewriter, L, this,
DeadInsts);
// Mark old value we replaced as possibly dead, so that it is eliminated