[llvm-commits] [llvm] r40776 - /llvm/trunk/lib/Transforms/Scalar/GVN.cpp

[Owen Anderson]

Author: resistor
Date: Fri Aug  3 06:03:26 2007
New Revision: 40776

URL: http://llvm.org/viewvc/llvm-project?rev=40776&view=rev
Log:
Fix a subtle iterator invalidation bug in a recursive algorithm.

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

Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=40776&r1=40775&r2=40776&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Fri Aug  3 06:03:26 2007
@@ -726,19 +726,21 @@
                                bool top_level) { 
                                  
   // If we have already computed this value, return the previously computed val.
-  Value *&V = Phis[BB];
+  Value *V = Phis[BB];
   if (V && ! top_level) return V;
   
   BasicBlock* singlePred = BB->getSinglePredecessor();
-  if (singlePred)
-    return V = GetValueForBlock(singlePred, orig, Phis);
-  
+  if (singlePred) {
+    V = GetValueForBlock(singlePred, orig, Phis);
+    Phis[BB] = V;
+    return V;
+  }
   // Otherwise, the idom is the loop, so we need to insert a PHI node.  Do so
   // now, then get values to fill in the incoming values for the PHI.
   PHINode *PN = new PHINode(orig->getType(), orig->getName()+".rle",
                             BB->begin());
   PN->reserveOperandSpace(std::distance(pred_begin(BB), pred_end(BB)));
-  V = PN;
+  Phis[BB] = PN;
   
   bool all_same = true;
   Value* first = 0;