[llvm-commits] [llvm] r54132 - /llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

[Owen Anderson]

Author: resistor
Date: Mon Jul 28 11:00:58 2008
New Revision: 54132

URL: http://llvm.org/viewvc/llvm-project?rev=54132&view=rev
Log:
Fix a subtle bug when removing instructions from memdep.  In very specific 
circumstances we could end up remapping a dependee to the same instruction 
that we're trying to remove.  Handle this properly by just falling back to
a conservative solution.

Modified:
    llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=54132&r1=54131&r2=54132&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Mon Jul 28 11:00:58 2008
@@ -528,6 +528,10 @@
       // If we have dep info for rem, set them to it
       BasicBlock::iterator RI = depGraphEntry->second.first;
       RI++;
+      
+      // If RI is rem, then we use rem's immediate successor.
+      if (RI == (BasicBlock::iterator)rem) RI++;
+      
       newDep = RI;
     } else if ( (depGraphEntry->second.first == NonLocal ||
                  depGraphEntry->second.first == None ) &&