[llvm-commits] [llvm] r111248 - /llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp

[Dan Gohman]

Author: djg
Date: Tue Aug 17 12:07:02 2010
New Revision: 111248

URL: http://llvm.org/viewvc/llvm-project?rev=111248&view=rev
Log:
Use the getUniquePredecessor() utility function, instead of doing
what it does manually.

Modified:
    llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp

Modified: llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp?rev=111248&r1=111247&r2=111248&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp Tue Aug 17 12:07:02 2010
@@ -97,23 +97,13 @@
 /// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,
 /// if possible.  The return value indicates success or failure.
 bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
-  pred_iterator PI(pred_begin(BB)), PE(pred_end(BB));
-  // Can't merge the entry block.  Don't merge away blocks who have their
-  // address taken: this is a bug if the predecessor block is the entry node
-  // (because we'd end up taking the address of the entry) and undesirable in
-  // any case.
-  if (pred_begin(BB) == pred_end(BB) ||
-      BB->hasAddressTaken()) return false;
-  
-  BasicBlock *PredBB = *PI++;
-  for (; PI != PE; ++PI)  // Search all predecessors, see if they are all same
-    if (*PI != PredBB) {
-      PredBB = 0;       // There are multiple different predecessors...
-      break;
-    }
+  // Don't merge away blocks who have their address taken.
+  if (BB->hasAddressTaken()) return false;
   
-  // Can't merge if there are multiple predecessors.
+  // Can't merge if there are multiple predecessors, or no predecessors.
+  BasicBlock *PredBB = BB->getUniquePredecessor();
   if (!PredBB) return false;
+
   // Don't break self-loops.
   if (PredBB == BB) return false;
   // Don't break invokes.