[llvm] r278858 - CodeGen: Don't dereference end() in MachineBasicBlock::CorrectExtraCFGEdges

[Duncan P. N. Exon Smith via llvm-commits]

Author: dexonsmith
Date: Tue Aug 16 16:46:03 2016
New Revision: 278858

URL: http://llvm.org/viewvc/llvm-project?rev=278858&view=rev
Log:
CodeGen: Don't dereference end() in MachineBasicBlock::CorrectExtraCFGEdges

The current MachineBasicBlock might be the last block, so FallThru may
be past the end().  Use getNextNode(), which will convert to nullptr,
rather than &*++, which is invalid if we reach the end().

Modified:
    llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp

Modified: llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp?rev=278858&r1=278857&r2=278858&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp Tue Aug 16 16:46:03 2016
@@ -1087,16 +1087,16 @@ bool MachineBasicBlock::CorrectExtraCFGE
 
   bool Changed = false;
 
-  MachineFunction::iterator FallThru = std::next(getIterator());
+  MachineBasicBlock *FallThru = getNextNode();
 
   if (!DestA && !DestB) {
     // Block falls through to successor.
-    DestA = &*FallThru;
-    DestB = &*FallThru;
+    DestA = FallThru;
+    DestB = FallThru;
   } else if (DestA && !DestB) {
     if (IsCond)
       // Block ends in conditional jump that falls through to successor.
-      DestB = &*FallThru;
+      DestB = FallThru;
   } else {
     assert(DestA && DestB && IsCond &&
            "CFG in a bad state. Cannot correct CFG edges");