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Revert r276136 "Use ValueOffsetPair to enhance value reuse during SCEV expansion."

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It causes Clang tests to fail after Windows self-host (PR28705).

(Also reverts follow-up r276139.)

llvm-svn: 276822
This commit is contained in:
Hans Wennborg
2016-07-26 23:25:13 +00:00
parent 918e81c3d4
commit 685e8ff953
5 changed files with 36 additions and 147 deletions
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31
llvm/lib/Analysis/ScalarEvolutionExpander.cpp
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@@ -1626,10 +1626,9 @@ Value *SCEVExpander::expandCodeFor(const SCEV *SH, Type *Ty) {
return V;
}
ScalarEvolution::ValueOffsetPair
SCEVExpander::FindValueInExprValueMap(const SCEV *S,
const Instruction *InsertPt) {
SetVector<ScalarEvolution::ValueOffsetPair> *Set = SE.getSCEVValues(S);
Value *SCEVExpander::FindValueInExprValueMap(const SCEV *S,
const Instruction *InsertPt) {
SetVector<Value *> *Set = SE.getSCEVValues(S);
// If the expansion is not in CanonicalMode, and the SCEV contains any
// sub scAddRecExpr type SCEV, it is required to expand the SCEV literally.
if (CanonicalMode || !SE.containsAddRecurrence(S)) {
@@ -1638,21 +1637,21 @@ SCEVExpander::FindValueInExprValueMap(const SCEV *S,
// Choose a Value from the set which dominates the insertPt.
// insertPt should be inside the Value's parent loop so as not to break
// the LCSSA form.
for (auto const &VOPair : *Set) {
Value *V = VOPair.first;
ConstantInt *Offset = VOPair.second;
for (auto const &Ent : *Set) {
Instruction *EntInst = nullptr;
if (V && isa<Instruction>(V) && (EntInst = cast<Instruction>(V)) &&
S->getType() == V->getType() &&
if (Ent && isa<Instruction>(Ent) &&
(EntInst = cast<Instruction>(Ent)) &&
S->getType() == Ent->getType() &&
EntInst->getFunction() == InsertPt->getFunction() &&
SE.DT.dominates(EntInst, InsertPt) &&
(SE.LI.getLoopFor(EntInst->getParent()) == nullptr ||
SE.LI.getLoopFor(EntInst->getParent())->contains(InsertPt)))
return {V, Offset};
SE.LI.getLoopFor(EntInst->getParent())->contains(InsertPt))) {
return Ent;
}
}
}
}
return {nullptr, nullptr};
return nullptr;
}
// The expansion of SCEV will either reuse a previous Value in ExprValueMap,
@@ -1700,14 +1699,10 @@ Value *SCEVExpander::expand(const SCEV *S) {
Builder.SetInsertPoint(InsertPt);
// Expand the expression into instructions.
ScalarEvolution::ValueOffsetPair VO = FindValueInExprValueMap(S, InsertPt);
Value *V = VO.first;
Value *V = FindValueInExprValueMap(S, InsertPt);
if (!V)
V = visit(S);
else if (VO.second) {
V = Builder.CreateSub(V, VO.second);
}
// Remember the expanded value for this SCEV at this location.
//
@@ -1920,7 +1915,7 @@ Value *SCEVExpander::findExistingExpansion(const SCEV *S,
// Use expand's logic which is used for reusing a previous Value in
// ExprValueMap.
if (Value *Val = FindValueInExprValueMap(S, At).first)
if (Value *Val = FindValueInExprValueMap(S, At))
return Val;
// There is potential to make this significantly smarter, but this simple