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Refactor loop condition check in a separate function.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41282 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2007-08-22 18:27:01 +00:00
parent ea0fa97334
commit dc52395353
1 changed files with 34 additions and 17 deletions
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51
lib/Transforms/Scalar/LoopIndexSplit.cpp
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@ -105,6 +105,13 @@ namespace {
/// Find cost of spliting loop L.
unsigned findSplitCost(Loop *L, SplitInfo &SD);
/// safeSplitCondition - Return true if it is possible to
/// split loop using given split condition.
bool safeSplitCondition(SplitInfo &SD);
/// splitLoop - Split current loop L in two loops using split information
/// SD. Update dominator information. Maintain LCSSA form.
bool splitLoop(SplitInfo &SD);
void initialize() {
@ -705,32 +712,28 @@ void LoopIndexSplit::removeBlocks(BasicBlock *DeadBB, Loop *LP,
}
/// splitLoop - Split current loop L in two loops using split information
/// SD. Update dominator information. Maintain LCSSA form.
bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
/// safeSplitCondition - Return true if it is possible to
/// split loop using given split condition.
bool LoopIndexSplit::safeSplitCondition(SplitInfo &SD) {
// True loop is original loop. False loop is cloned loop.
BasicBlock *TL_Preheader = L->getLoopPreheader();
BasicBlock *TL_SplitCondBlock = SD.SplitCondition->getParent();
BasicBlock *TL_Latch = L->getLoopLatch();
BasicBlock *TL_Header = L->getHeader();
BranchInst *TL_SplitTerminator =
cast<BranchInst>(TL_SplitCondBlock->getTerminator());
BasicBlock *SplitCondBlock = SD.SplitCondition->getParent();
// FIXME - Unable to handle triange loops at the moment.
// Unable to handle triange loops at the moment.
// In triangle loop, split condition is in header and one of the
// the split destination is loop latch. If split condition is EQ
// then such loops are already handle in processOneIterationLoop().
BasicBlock *Succ0 = TL_SplitTerminator->getSuccessor(0);
BasicBlock *Succ1 = TL_SplitTerminator->getSuccessor(1);
if (TL_Header == TL_SplitCondBlock
&& (TL_Latch == Succ0 || TL_Latch == Succ1))
BasicBlock *Latch = L->getLoopLatch();
BranchInst *SplitTerminator =
cast<BranchInst>(SplitCondBlock->getTerminator());
BasicBlock *Succ0 = SplitTerminator->getSuccessor(0);
BasicBlock *Succ1 = SplitTerminator->getSuccessor(1);
if (L->getHeader() == SplitCondBlock
&& (Latch == Succ0 || Latch == Succ1))
return false;
// If one of the split condition branch is post dominating other then loop
// index split is not appropriate.
if (DT->dominates(Succ0, TL_Latch) || DT->dominates(Succ1, TL_Latch))
if (DT->dominates(Succ0, Latch) || DT->dominates(Succ1, Latch))
return false;
// If one of the split condition branch is a predecessor of the other
@ -744,6 +747,20 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
if (Succ0 == *PI)
return false;
return true;
}
/// splitLoop - Split current loop L in two loops using split information
/// SD. Update dominator information. Maintain LCSSA form.
bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
if (!safeSplitCondition(SD))
return false;
// True loop is original loop. False loop is cloned loop.
BasicBlock *TL_SplitCondBlock = SD.SplitCondition->getParent();
BasicBlock *TL_Preheader = L->getLoopPreheader();
bool SignedPredicate = ExitCondition->isSignedPredicate();
//[*] Calculate True loop's new Exit Value in loop preheader.
// TL_ExitValue = min(SplitValue, ExitValue)