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Use 'continue' to reduce nesting in this loop. No functionality change.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51399 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-05-22 00:53:38 +00:00
parent ddc4ee82b5
commit 29d929363d
1 changed files with 55 additions and 58 deletions
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113
lib/Transforms/Scalar/LICM.cpp
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@ -787,72 +787,69 @@ void LICM::FindPromotableValuesInLoop(
// We can promote this alias set if it has a store, if it is a "Must" alias // We can promote this alias set if it has a store, if it is a "Must" alias
// set, if the pointer is loop invariant, and if we are not eliminating any // set, if the pointer is loop invariant, and if we are not eliminating any
// volatile loads or stores. // volatile loads or stores.
if (!AS.isForwardingAliasSet() && AS.isMod() && AS.isMustAlias() && if (AS.isForwardingAliasSet() || !AS.isMod() || !AS.isMustAlias() ||
!AS.isVolatile() && CurLoop->isLoopInvariant(AS.begin()->first)) { AS.isVolatile() || !CurLoop->isLoopInvariant(AS.begin()->first))
assert(!AS.empty() && continue;
"Must alias set should have at least one pointer element in it!");
Value *V = AS.begin()->first;
// Check that all of the pointers in the alias set have the same type. We assert(!AS.empty() &&
// cannot (yet) promote a memory location that is loaded and stored in "Must alias set should have at least one pointer element in it!");
// different sizes. Value *V = AS.begin()->first;
// Check that all of the pointers in the alias set have the same type. We
// cannot (yet) promote a memory location that is loaded and stored in
// different sizes.
{
bool PointerOk = true; bool PointerOk = true;
for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I) for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I)
if (V->getType() != I->first->getType()) { if (V->getType() != I->first->getType()) {
PointerOk = false; PointerOk = false;
break; break;
} }
if (!PointerOk)
// If one use of value V inside the loop is safe then it is OK to promote continue;
// this value. On the otherside if there is not any unsafe use inside the
// loop then also it is OK to promote this value. Otherwise it is
// unsafe to promote this value.
if (PointerOk) {
bool oneSafeUse = false;
bool oneUnsafeUse = false;
for(Value::use_iterator UI = V->use_begin(), UE = V->use_end();
UI != UE; ++UI) {
Instruction *Use = dyn_cast<Instruction>(*UI);
if (!Use || !CurLoop->contains(Use->getParent()))
continue;
for (SmallVector<Instruction *, 4>::iterator
ExitI = LoopExits.begin(), ExitE = LoopExits.end();
ExitI != ExitE; ++ExitI) {
Instruction *Ex = *ExitI;
if (!isa<PHINode>(Use) && DT->dominates(Use, Ex)) {
oneSafeUse = true;
break;
}
else
oneUnsafeUse = true;
}
if (oneSafeUse)
break;
}
if (oneSafeUse)
PointerOk = true;
else if (!oneUnsafeUse)
PointerOk = true;
else
PointerOk = false;
}
if (PointerOk) {
const Type *Ty = cast<PointerType>(V->getType())->getElementType();
AllocaInst *AI = new AllocaInst(Ty, 0, V->getName()+".tmp", FnStart);
PromotedValues.push_back(std::make_pair(AI, V));
// Update the AST and alias analysis.
CurAST->copyValue(V, AI);
for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I)
ValueToAllocaMap.insert(std::make_pair(I->first, AI));
DOUT << "LICM: Promoting value: " << *V << "\n";
}
} }
// If one use of value V inside the loop is safe then it is OK to promote
// this value. On the otherside if there is not any unsafe use inside the
// loop then also it is OK to promote this value. Otherwise it is
// unsafe to promote this value.
bool oneSafeUse = false;
bool oneUnsafeUse = false;
for(Value::use_iterator UI = V->use_begin(), UE = V->use_end();
UI != UE; ++UI) {
Instruction *Use = dyn_cast<Instruction>(*UI);
if (!Use || !CurLoop->contains(Use->getParent()))
continue;
for (SmallVector<Instruction *, 4>::iterator
ExitI = LoopExits.begin(), ExitE = LoopExits.end();
ExitI != ExitE; ++ExitI) {
Instruction *Ex = *ExitI;
if (!isa<PHINode>(Use) && DT->dominates(Use, Ex)) {
oneSafeUse = true;
break;
} else
oneUnsafeUse = true;
}
if (oneSafeUse)
break;
}
if (!oneSafeUse && oneUnsafeUse)
continue;
const Type *Ty = cast<PointerType>(V->getType())->getElementType();
AllocaInst *AI = new AllocaInst(Ty, 0, V->getName()+".tmp", FnStart);
PromotedValues.push_back(std::make_pair(AI, V));
// Update the AST and alias analysis.
CurAST->copyValue(V, AI);
for (AliasSet::iterator I = AS.begin(), E = AS.end(); I != E; ++I)
ValueToAllocaMap.insert(std::make_pair(I->first, AI));
DOUT << "LICM: Promoting value: " << *V << "\n";
} }
} }