[llvm-commits] CVS: llvm/lib/CodeGen/BranchFolding.cpp

[Dale Johannesen]

Changes in directory llvm/lib/CodeGen:

BranchFolding.cpp updated: 1.56 -> 1.57
---
Log message:

Fix for PR1444: http://llvm.org/PR1444 : do not create two successors to the same block.
Temporarily, this breaks CodeGen/Generic/2006-02-12-InsertLibraryCall.ll
by exposing an unrelated latent problem; working on that.


---
Diffs of the changes:  (+10 -2)

 BranchFolding.cpp |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)


Index: llvm/lib/CodeGen/BranchFolding.cpp
diff -u llvm/lib/CodeGen/BranchFolding.cpp:1.56 llvm/lib/CodeGen/BranchFolding.cpp:1.57
--- llvm/lib/CodeGen/BranchFolding.cpp:1.56	Wed May 23 16:07:20 2007
+++ llvm/lib/CodeGen/BranchFolding.cpp	Thu May 24 12:39:32 2007
@@ -717,12 +717,20 @@
         I->getOperand(i).setMachineBasicBlock(New);
   }
 
-  // Update the successor information.
+  // Update the successor information.  If New was already a successor, just
+  // remove the link to Old instead of creating another one.  PR 1444.
+  bool HadSuccessorNew = false;
   std::vector<MachineBasicBlock*> Succs(BB->succ_begin(), BB->succ_end());
   for (int i = Succs.size()-1; i >= 0; --i)
+    if (Succs[i] == New) {
+      HadSuccessorNew = true;
+      break;
+    }
+  for (int i = Succs.size()-1; i >= 0; --i)
     if (Succs[i] == Old) {
       BB->removeSuccessor(Old);
-      BB->addSuccessor(New);
+      if (!HadSuccessorNew)
+        BB->addSuccessor(New);
     }
 }