[llvm-commits] [llvm] r90708 - in /llvm/trunk: lib/Transforms/Scalar/JumpThreading.cpp test/Transforms/JumpThreading/crash.ll

[Chris Lattner]

Author: lattner
Date: Sun Dec  6 11:17:23 2009
New Revision: 90708

URL: http://llvm.org/viewvc/llvm-project?rev=90708&view=rev
Log:
fix PR5698

Modified:
    llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
    llvm/trunk/test/Transforms/JumpThreading/crash.ll

Modified: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp?rev=90708&r1=90707&r2=90708&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp Sun Dec  6 11:17:23 2009
@@ -718,6 +718,11 @@
       if (PredSI->getSuccessor(PredCase) != DestBB &&
           DestSI->getSuccessor(i) != DestBB)
         continue;
+      
+      // Do not forward this if it already goes to this destination, this would
+      // be an infinite loop.
+      if (PredSI->getSuccessor(PredCase) == DestSucc)
+        continue;
 
       // Otherwise, we're safe to make the change.  Make sure that the edge from
       // DestSI to DestSucc is not critical and has no PHI nodes.

Modified: llvm/trunk/test/Transforms/JumpThreading/crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/JumpThreading/crash.ll?rev=90708&r1=90707&r2=90708&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/JumpThreading/crash.ll (original)
+++ llvm/trunk/test/Transforms/JumpThreading/crash.ll Sun Dec  6 11:17:23 2009
@@ -212,3 +212,25 @@
 bb61:                                            
   ret void
 }
+
+
+; PR5698
+define void @test7(i32 %x) {
+tailrecurse:
+  switch i32 %x, label %return [
+    i32 2, label %bb2
+    i32 3, label %bb
+  ]
+
+bb:         
+  switch i32 %x, label %return [
+    i32 2, label %bb2
+    i32 3, label %tailrecurse
+  ]
+
+bb2:        
+  ret void
+
+return:     
+  ret void
+}