Recompute dominator tree after DCE.

bug:22031382
Change-Id: Ifebe169897b76872015e3ce0ed7d0a9662f80cef

1 files changed, 6 insertions, 0 deletions

diff --git a/compiler/optimizing/boolean_simplifier.cc b/compiler/optimizing/boolean_simplifier.cc
index 8100a29f32..daf7d67746 100644
--- a/compiler/optimizing/boolean_simplifier.cc
+++ b/compiler/optimizing/boolean_simplifier.cc
@@ -141,6 +141,12 @@ void HBooleanSimplifier::TryRemovingBooleanSelection(HBasicBlock* block) {
   block->MergeWith(false_block);
   block->MergeWith(merge_block);
 
+  // No need to update any dominance information, as we are simplifying
+  // a simple diamond shape, where the join block is merged with the
+  // entry block. Any following blocks would have had the join block
+  // as a dominator, and `MergeWith` handles changing that to the
+  // entry block.
+
   // Remove the original condition if it is now unused.
   if (!if_condition->HasUses()) {
     if_condition->GetBlock()->RemoveInstructionOrPhi(if_condition);