Revert r275883 and r275891. They seem to cause PR28608.
Revert "[LoopSimplify] Update LCSSA after separating nested loops."
This reverts commit r275891.
Revert "[LCSSA] Post-process PHI-nodes created by SSAUpdate when constructing LCSSA form."
This reverts commit r275883.
llvm-svn: 276064
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index 2846e8f..b3a928b 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -327,8 +327,6 @@
else
NewOuter->addChildLoop(L->removeChildLoop(SubLoops.begin() + I));
- SmallVector<BasicBlock *, 8> OuterLoopBlocks;
- OuterLoopBlocks.push_back(NewBB);
// Now that we know which blocks are in L and which need to be moved to
// OuterLoop, move any blocks that need it.
for (unsigned i = 0; i != L->getBlocks().size(); ++i) {
@@ -336,53 +334,12 @@
if (!BlocksInL.count(BB)) {
// Move this block to the parent, updating the exit blocks sets
L->removeBlockFromLoop(BB);
- if ((*LI)[BB] == L) {
+ if ((*LI)[BB] == L)
LI->changeLoopFor(BB, NewOuter);
- OuterLoopBlocks.push_back(BB);
- }
--i;
}
}
- // Split edges to exit blocks from the inner loop, if they emerged in the
- // process of separating the outer one.
- SmallVector<BasicBlock *, 8> ExitBlocks;
- L->getExitBlocks(ExitBlocks);
- SmallSetVector<BasicBlock *, 8> ExitBlockSet(ExitBlocks.begin(),
- ExitBlocks.end());
- for (BasicBlock *ExitBlock : ExitBlockSet) {
- if (any_of(predecessors(ExitBlock),
- [L](BasicBlock *BB) { return !L->contains(BB); })) {
- rewriteLoopExitBlock(L, ExitBlock, DT, LI, PreserveLCSSA);
- }
- }
-
- if (PreserveLCSSA) {
- // Fix LCSSA form for L. Some values, which previously were only used inside
- // L, can now be used in NewOuter loop. We need to insert phi-nodes for them
- // in corresponding exit blocks.
-
- // Go through all instructions in OuterLoopBlocks and check if they are
- // using operands from the inner loop. In this case we'll need to fix LCSSA
- // for these instructions.
- SmallSetVector<Instruction *, 8> WorklistSet;
- for (BasicBlock *OuterBB: OuterLoopBlocks) {
- for (Instruction &I : *OuterBB) {
- for (Value *Op : I.operands()) {
- Instruction *OpI = dyn_cast<Instruction>(Op);
- if (!OpI || !L->contains(OpI))
- continue;
- WorklistSet.insert(OpI);
- }
- }
- }
- SmallVector<Instruction *, 8> Worklist(WorklistSet.begin(),
- WorklistSet.end());
- formLCSSAForInstructions(Worklist, *DT, *LI);
- assert(NewOuter->isRecursivelyLCSSAForm(*DT) &&
- "LCSSA is broken after separating nested loops!");
- }
-
return NewOuter;
}
@@ -584,12 +541,17 @@
SmallSetVector<BasicBlock *, 8> ExitBlockSet(ExitBlocks.begin(),
ExitBlocks.end());
for (BasicBlock *ExitBlock : ExitBlockSet) {
- if (any_of(predecessors(ExitBlock),
- [L](BasicBlock *BB) { return !L->contains(BB); })) {
- rewriteLoopExitBlock(L, ExitBlock, DT, LI, PreserveLCSSA);
- ++NumInserted;
- Changed = true;
- }
+ for (pred_iterator PI = pred_begin(ExitBlock), PE = pred_end(ExitBlock);
+ PI != PE; ++PI)
+ // Must be exactly this loop: no subloops, parent loops, or non-loop preds
+ // allowed.
+ if (!L->contains(*PI)) {
+ if (rewriteLoopExitBlock(L, ExitBlock, DT, LI, PreserveLCSSA)) {
+ ++NumInserted;
+ Changed = true;
+ }
+ break;
+ }
}
// If the header has more than two predecessors at this point (from the