diff options
Diffstat (limited to 'lib/Transforms/Scalar/LoopUnswitch.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/LoopUnswitch.cpp | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp index 01a99af143..e05f29c3e1 100644 --- a/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -258,6 +258,7 @@ bool LoopUnswitch::processCurrentLoop() { if (LoopCond && SI->getNumCases() > 1) { // Find a value to unswitch on: // FIXME: this should chose the most expensive case! + // FIXME: scan for a case with a non-critical edge? Constant *UnswitchVal = SI->getCaseValue(1); // Do not process same value again and again. if (!UnswitchedVals.insert(UnswitchVal)) @@ -560,6 +561,8 @@ void LoopUnswitch::SplitExitEdges(Loop *L, BasicBlock *ExitBlock = ExitBlocks[i]; SmallVector<BasicBlock *, 4> Preds(pred_begin(ExitBlock), pred_end(ExitBlock)); + // Although SplitBlockPredecessors doesn't preserve loop-simplify in + // general, if we call it on all predecessors of all exits then it does. SplitBlockPredecessors(ExitBlock, Preds.data(), Preds.size(), ".us-lcssa", this); } @@ -915,10 +918,11 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, // Found a dead case value. Don't remove PHI nodes in the // successor if they become single-entry, those PHI nodes may // be in the Users list. - + BasicBlock *Switch = SI->getParent(); BasicBlock *SISucc = SI->getSuccessor(DeadCase); BasicBlock *Latch = L->getLoopLatch(); + if (!SI->findCaseDest(SISucc)) continue; // Edge is critical. // If the DeadCase successor dominates the loop latch, then the // transformation isn't safe since it will delete the sole predecessor edge // to the latch. |