if (!safeExitingBlock(SD, ExitCondition->getParent()))
return false;
+ // If split condition is not safe then do not process this loop.
+ // For example,
+ // for(int i = 0; i < N; i++) {
+ // if ( i == XYZ) {
+ // A;
+ // else
+ // B;
+ // }
+ // C;
+ // D;
+ // }
+ if (!safeSplitCondition(SD))
+ return false;
+
// Update CFG.
// Replace index variable with split value in loop body. Loop body is executed
bool LoopIndexSplit::safeSplitCondition(SplitInfo &SD) {
BasicBlock *SplitCondBlock = SD.SplitCondition->getParent();
-
- // 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 *Latch = L->getLoopLatch();
+ 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 split condition branches heads do not have single predecessor,
- // SplitCondBlock, then is not possible to remove inactive branch.
- if (!Succ0->getSinglePredecessor() || !Succ1->getSinglePredecessor())
- return false;
// Finally this split condition is safe only if merge point for
// split condition branch is loop latch. This check along with previous
if (!safeSplitCondition(SD))
return false;
+ BasicBlock *SplitCondBlock = SD.SplitCondition->getParent();
+
+ // 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 *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 split condition branches heads do not have single predecessor,
+ // SplitCondBlock, then is not possible to remove inactive branch.
+ if (!Succ0->getSinglePredecessor() || !Succ1->getSinglePredecessor())
+ return false;
+
// After loop is cloned there are two loops.
//
// First loop, referred as ALoop, executes first part of loop's iteration