[llvm-commits] [llvm] r69151 - /llvm/trunk/lib/VMCore/Value.cpp

[Nick Lewycky]

Author: nicholas
Date: Wed Apr 15 01:23:41 2009
New Revision: 69151

URL: http://llvm.org/viewvc/llvm-project?rev=69151&view=rev
Log:
Limit the number of times we're willing to chase pointers. Removes an O(n^2)
problem from instcombine.

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

Modified: llvm/trunk/lib/VMCore/Value.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Value.cpp?rev=69151&r1=69150&r2=69151&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/Value.cpp (original)
+++ llvm/trunk/lib/VMCore/Value.cpp Wed Apr 15 01:23:41 2009
@@ -365,6 +365,7 @@
   if (!isa<PointerType>(getType()))
     return this;
   Value *V = this;
+  unsigned MaxLookup = 6;
   do {
     if (Instruction *I = dyn_cast<Instruction>(V)) {
       if (!isa<BitCastInst>(I) && !isa<GetElementPtrInst>(I))
@@ -379,7 +380,8 @@
       return V;
     }
     assert(isa<PointerType>(V->getType()) && "Unexpected operand type!");
-  } while (1);
+  } while (--MaxLookup);
+  return V;
 }
 
 /// DoPHITranslation - If this value is a PHI node with CurBB as its parent,