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Revert "LSR: try not to blow up solving combinatorial problems brute force."

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Some units tests crashed on a different platform.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160341 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2012-07-17 05:05:21 +00:00
parent 6a51a7aea5
commit 81ba5060ea
1 changed files with 28 additions and 51 deletions
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79
lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@ -3006,63 +3006,42 @@ LSRInstance::CollectLoopInvariantFixupsAndFormulae() {
/// CollectSubexprs - Split S into subexpressions which can be pulled out into /// CollectSubexprs - Split S into subexpressions which can be pulled out into
/// separate registers. If C is non-null, multiply each subexpression by C. /// separate registers. If C is non-null, multiply each subexpression by C.
static const SCEV *CollectSubexprs(const SCEV *S, const SCEVConstant *C, static void CollectSubexprs(const SCEV *S, const SCEVConstant *C,
SmallVectorImpl<const SCEV *> &Ops, SmallVectorImpl<const SCEV *> &Ops,
const Loop *L, const Loop *L,
ScalarEvolution &SE, ScalarEvolution &SE) {
unsigned Depth = 0) {
// Arbitrarily cap recursion to protect compile time.
if (Depth >= 3)
return S;
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
// Break out add operands. // Break out add operands.
for (SCEVAddExpr::op_iterator I = Add->op_begin(), E = Add->op_end(); for (SCEVAddExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
I != E; ++I) { I != E; ++I)
const SCEV *Remainder = CollectSubexprs(*I, C, Ops, L, SE, Depth+1); CollectSubexprs(*I, C, Ops, L, SE);
if (Remainder) return;
Ops.push_back(C ? SE.getMulExpr(C, Remainder) : Remainder);
}
return NULL;
} else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) { } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
// Split a non-zero base out of an addrec. // Split a non-zero base out of an addrec.
if (AR->getStart()->isZero()) if (!AR->getStart()->isZero()) {
return S; CollectSubexprs(SE.getAddRecExpr(SE.getConstant(AR->getType(), 0),
AR->getStepRecurrence(SE),
const SCEV *Remainder = CollectSubexprs(AR->getStart(), AR->getLoop(),
C, Ops, L, SE, Depth+1); //FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
// Split the non-zero AddRec unless it is part of a nested recurrence that SCEV::FlagAnyWrap),
// does not pertain to this loop. C, Ops, L, SE);
if (AR->getLoop() == L || !isa<SCEVAddRecExpr>(Remainder)) { CollectSubexprs(AR->getStart(), C, Ops, L, SE);
if (Remainder) { return;
Ops.push_back(C ? SE.getMulExpr(C, Remainder) : Remainder);
Remainder = NULL;
}
}
if (Remainder != AR->getStart()) {
if (!Remainder)
Remainder = SE.getConstant(AR->getType(), 0);
return SE.getAddRecExpr(Remainder,
AR->getStepRecurrence(SE),
AR->getLoop(),
//FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
SCEV::FlagAnyWrap);
} }
} else if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) { } else if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
// Break (C * (a + b + c)) into C*a + C*b + C*c. // Break (C * (a + b + c)) into C*a + C*b + C*c.
if (Mul->getNumOperands() != 2) if (Mul->getNumOperands() == 2)
return S; if (const SCEVConstant *Op0 =
if (const SCEVConstant *Op0 = dyn_cast<SCEVConstant>(Mul->getOperand(0))) {
dyn_cast<SCEVConstant>(Mul->getOperand(0))) { CollectSubexprs(Mul->getOperand(1),
C = C ? cast<SCEVConstant>(SE.getMulExpr(C, Op0)) : Op0; C ? cast<SCEVConstant>(SE.getMulExpr(C, Op0)) : Op0,
const SCEV *Remainder = Ops, L, SE);
CollectSubexprs(Mul->getOperand(1), C, Ops, L, SE, Depth+1); return;
if (Remainder) }
Ops.push_back(SE.getMulExpr(C, Remainder));
return NULL;
}
} }
return S;
// Otherwise use the value itself, optionally with a scale applied.
Ops.push_back(C ? SE.getMulExpr(C, S) : S);
} }
/// GenerateReassociations - Split out subexpressions from adds and the bases of /// GenerateReassociations - Split out subexpressions from adds and the bases of
@ -3077,9 +3056,7 @@ void LSRInstance::GenerateReassociations(LSRUse &LU, unsigned LUIdx,
const SCEV *BaseReg = Base.BaseRegs[i]; const SCEV *BaseReg = Base.BaseRegs[i];
SmallVector<const SCEV *, 8> AddOps; SmallVector<const SCEV *, 8> AddOps;
const SCEV *Remainder = CollectSubexprs(BaseReg, 0, AddOps, L, SE); CollectSubexprs(BaseReg, 0, AddOps, L, SE);
if (Remainder)
AddOps.push_back(Remainder);
if (AddOps.size() == 1) continue; if (AddOps.size() == 1) continue;