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-rw-r--r--compiler/optimizing/nodes.cc18
1 files changed, 13 insertions, 5 deletions
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 2d3dcf746b..7a8b463d13 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -383,19 +383,27 @@ void HGraph::ComputeTryBlockInformation() {
}
void HGraph::SimplifyCFG() {
- // Simplify the CFG for future analysis, and code generation:
+// Simplify the CFG for future analysis, and code generation:
// (1): Split critical edges.
- // (2): Simplify loops by having only one back edge, and one preheader.
+ // (2): Simplify loops by having only one preheader.
// NOTE: We're appending new blocks inside the loop, so we need to use index because iterators
// can be invalidated. We remember the initial size to avoid iterating over the new blocks.
for (size_t block_id = 0u, end = blocks_.size(); block_id != end; ++block_id) {
HBasicBlock* block = blocks_[block_id];
if (block == nullptr) continue;
- if (block->NumberOfNormalSuccessors() > 1) {
- for (size_t j = 0; j < block->GetSuccessors().size(); ++j) {
+ if (block->GetSuccessors().size() > 1) {
+ // Only split normal-flow edges. We cannot split exceptional edges as they
+ // are synthesized (approximate real control flow), and we do not need to
+ // anyway. Moves that would be inserted there are performed by the runtime.
+ for (size_t j = 0, e = block->NumberOfNormalSuccessors(); j < e; ++j) {
HBasicBlock* successor = block->GetSuccessors()[j];
DCHECK(!successor->IsCatchBlock());
- if (successor->GetPredecessors().size() > 1) {
+ if (successor == exit_block_) {
+ // Throw->TryBoundary->Exit. Special case which we do not want to split
+ // because Goto->Exit is not allowed.
+ DCHECK(block->IsSingleTryBoundary());
+ DCHECK(block->GetSinglePredecessor()->GetLastInstruction()->IsThrow());
+ } else if (successor->GetPredecessors().size() > 1) {
SplitCriticalEdge(block, successor);
--j;
}