[llvm-commits] [llvm] r47957 - in /llvm/trunk: include/llvm/CodeGen/SelectionDAGNodes.h lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

[Dale Johannesen]

Author: johannes
Date: Wed Mar  5 13:14:03 2008
New Revision: 47957

URL: http://llvm.org/viewvc/llvm-project?rev=47957&view=rev
Log:
Clarify that CALLSEQ_START..END may not be nested,
and add some protection against creating such.


Modified:
    llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
    llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h?rev=47957&r1=47956&r2=47957&view=diff

==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h Wed Mar  5 13:14:03 2008
@@ -529,6 +529,7 @@
     // a call sequence, and carry arbitrary information that target might want
     // to know.  The first operand is a chain, the rest are specified by the
     // target and not touched by the DAG optimizers.
+    // CALLSEQ_START..CALLSEQ_END pairs may not be nested.
     CALLSEQ_START,  // Beginning of a call sequence
     CALLSEQ_END,    // End of a call sequence
     

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp?rev=47957&r1=47956&r2=47957&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp Wed Mar  5 13:14:03 2008
@@ -1266,6 +1266,13 @@
     // The only option for this is to custom lower it.
     Tmp3 = TLI.LowerOperation(Result.getValue(0), DAG);
     assert(Tmp3.Val && "Target didn't custom lower this node!");
+    // A call within a calling sequence must be legalized to something
+    // other than the normal CALLSEQ_END.  Violating this gets Legalize
+    // into an infinite loop.
+    assert ((!IsLegalizingCall ||
+             Node->getOpcode() != ISD::CALL ||
+             Tmp3.Val->getOpcode() != ISD::CALLSEQ_END) &&
+            "Nested CALLSEQ_START..CALLSEQ_END not supported.");
 
     // The number of incoming and outgoing values should match; unless the final
     // outgoing value is a flag.