[llvm-commits] [llvm] r168829 - /llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp

[Bill Wendling]

Author: void
Date: Wed Nov 28 17:23:48 2012
New Revision: 168829

URL: http://llvm.org/viewvc/llvm-project?rev=168829&view=rev
Log:
When we delete a dead basic block, see if any of its successors are dead and
delete those as well.

Modified:
    llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp?rev=168829&r1=168828&r2=168829&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp Wed Nov 28 17:23:48 2012
@@ -194,9 +194,19 @@
           WorkList.insert(*II);
     }
 
-    for (SmallPtrSet<BasicBlock*, 8>::iterator
-           I = WorkList.begin(), E = WorkList.end(); I != E; ++I)
-      DeleteDeadBlock(*I);
+    // Delete the dead blocks and any of their dead successors.
+    while (!WorkList.empty()) {
+      BasicBlock *BB = *WorkList.begin();
+      WorkList.erase(BB);
+      SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
+
+      DeleteDeadBlock(BB);
+      
+      for (SmallVectorImpl<BasicBlock*>::iterator
+             II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
+        if (pred_begin(*II) == pred_end(*II))
+          WorkList.insert(*II);
+    }
 
     // Merge pairs of basic blocks with unconditional branches, connected by
     // a single edge.