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Revert r80926. It causes loop unswitch assertion and slow down some JIT tests significantly.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81101 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2009-09-06 02:26:10 +00:00
parent 92a97a9166
commit 8f78a58e14
11 changed files with 195 additions and 287 deletions
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40
lib/Transforms/Utils/LoopSimplify.cpp
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@ -69,8 +69,8 @@ namespace {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
// We need loop information to identify the loops...
AU.addRequiredTransitive<LoopInfo>();
AU.addRequiredTransitive<DominatorTree>();
AU.addRequired<LoopInfo>();
AU.addRequired<DominatorTree>();
AU.addPreserved<LoopInfo>();
AU.addPreserved<DominatorTree>();
@ -83,13 +83,9 @@ namespace {
void verifyAnalysis() const {
#ifndef NDEBUG
LoopInfo *NLI = &getAnalysis<LoopInfo>();
for (LoopInfo::iterator I = NLI->begin(), E = NLI->end(); I != E; ++I) {
// Sanity check: Check basic loop invariants.
for (LoopInfo::iterator I = NLI->begin(), E = NLI->end(); I != E; ++I)
(*I)->verifyLoop();
// Check the special guarantees that LoopSimplify makes.
assert((*I)->isLoopSimplifyForm());
}
#endif
#endif
}
private:
@ -350,6 +346,15 @@ BasicBlock *LoopSimplify::InsertPreheaderForLoop(Loop *L) {
BasicBlock *NewBB =
SplitBlockPredecessors(Header, &OutsideBlocks[0], OutsideBlocks.size(),
".preheader", this);
//===--------------------------------------------------------------------===//
// Update analysis results now that we have performed the transformation
//
// We know that we have loop information to update... update it now.
if (Loop *Parent = L->getParentLoop())
Parent->addBasicBlockToLoop(NewBB, LI->getBase());
// Make sure that NewBB is put someplace intelligent, which doesn't mess up
// code layout too horribly.
@ -372,6 +377,17 @@ BasicBlock *LoopSimplify::RewriteLoopExitBlock(Loop *L, BasicBlock *Exit) {
LoopBlocks.size(), ".loopexit",
this);
// Update Loop Information - we know that the new block will be in whichever
// loop the Exit block is in. Note that it may not be in that immediate loop,
// if the successor is some other loop header. In that case, we continue
// walking up the loop tree to find a loop that contains both the successor
// block and the predecessor block.
Loop *SuccLoop = LI->getLoopFor(Exit);
while (SuccLoop && !SuccLoop->contains(L->getHeader()))
SuccLoop = SuccLoop->getParentLoop();
if (SuccLoop)
SuccLoop->addBasicBlockToLoop(NewBB, LI->getBase());
return NewBB;
}
@ -505,6 +521,10 @@ Loop *LoopSimplify::SeparateNestedLoop(Loop *L) {
else
LI->changeTopLevelLoop(L, NewOuter);
// This block is going to be our new header block: add it to this loop and all
// parent loops.
NewOuter->addBasicBlockToLoop(NewBB, LI->getBase());
// L is now a subloop of our outer loop.
NewOuter->addChildLoop(L);
@ -512,10 +532,6 @@ Loop *LoopSimplify::SeparateNestedLoop(Loop *L) {
I != E; ++I)
NewOuter->addBlockEntry(*I);
// Now reset the header in L, which had been moved by
// SplitBlockPredecessors for the outer loop.
L->moveToHeader(Header);
// Determine which blocks should stay in L and which should be moved out to
// the Outer loop now.
std::set<BasicBlock*> BlocksInL;