[llvm-commits] [llvm] r40564 - /llvm/trunk/lib/VMCore/Dominators.cpp

[Devang Patel]

Author: dpatel
Date: Fri Jul 27 14:13:43 2007
New Revision: 40564

URL: http://llvm.org/viewvc/llvm-project?rev=40564&view=rev
Log:
Fix edge cases in handling basic block split.

Modified:
    llvm/trunk/lib/VMCore/Dominators.cpp

Modified: llvm/trunk/lib/VMCore/Dominators.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Dominators.cpp?rev=40564&r1=40563&r2=40564&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/Dominators.cpp (original)
+++ llvm/trunk/lib/VMCore/Dominators.cpp Fri Jul 27 14:13:43 2007
@@ -616,7 +616,11 @@
        PI != PE; ++PI)
       PredBlocks.push_back(*PI);  
 
-  assert(!PredBlocks.empty() && "No predblocks??");
+  if (PredBlocks.empty())
+    // If NewBB does not have any predecessors then it is a entry block.
+    // In this case, NewBB and its successor NewBBSucc dominates all
+    // other blocks.
+    return;
 
   DominatorTree &DT = getAnalysis<DominatorTree>();
   bool NewBBDominatesNewBBSucc = true;
@@ -643,8 +647,13 @@
         else
           ++SetI;
       }
-      
-      addBasicBlock(NewBB, Set);
+
+      DominanceFrontier::iterator NewBBI = find(NewBB);
+      if (NewBBI != end()) {
+        DominanceFrontier::DomSetType NewBBSet = NewBBI->second;
+        NewBBSet.insert(Set.begin(), Set.end());
+      } else 
+        addBasicBlock(NewBB, Set);
     }
     
   } else {