PHI nodes are not allowed to exist with zero incoming values, check that

there aren't any like this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4044 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index 51e0d2dddd..1663ddf6b7 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -17,6 +17,7 @@
 //  * Only phi nodes can be self referential: 'add int %0, %0 ; <int>:0' is bad
 //  * PHI nodes must have an entry for each predecessor, with no extras.
 //  * PHI nodes must be the first thing in a basic block, all grouped together
+//  * PHI nodes must have at least one entry
 //  * All basic blocks should only end with terminator insts, not contain them
 //  * The entry node to a function must not have predecessors
 //  * All Instructions must be embeded into a basic block
@@ -258,6 +259,12 @@ void Verifier::visitPHINode(PHINode &PN) {
           "PHI nodes not grouped at top of basic block!",
           &PN, PN.getParent());
 
+  // Ensure that PHI nodes have at least one entry!
+  Assert1(PN.getNumIncomingValues() != 0,
+          "PHI nodes must have at least one entry.  If the block is dead, "
+          "the PHI should be removed!",
+          &PN);
+
   std::vector<BasicBlock*> Preds(pred_begin(PN.getParent()),
                                  pred_end(PN.getParent()));
   // Loop over all of the incoming values, make sure that there are