Adjust ScheduleDAGSDNodes::RegDefIter for patchpoints

PATCHPOINT is a strange pseudo-instruction. Depending on how it is used, and
whether or not the AnyReg calling convention is being used, it might or might
not define a value. However, its TableGen definition says that it defines one
value, and so when it doesn't, the code in ScheduleDAGSDNodes::RegDefIter
becomes confused and the code that uses the RegDefIter will try to get the
register class of the MVT::Other type associated with the PATCHPOINT's chain
result (under certain circumstances).

This will be covered by the PPC64 PatchPoint test cases once that support is
re-committed.

llvm-svn: 225907

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 8b9f6186fcf..f2b18fc84bf 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -551,6 +551,14 @@ void ScheduleDAGSDNodes::RegDefIter::InitNodeNumDefs() {
     NodeNumDefs = 0;
     return;
   }
+  if (POpc == TargetOpcode::PATCHPOINT &&
+      Node->getValueType(0) == MVT::Other) {
+    // PATCHPOINT is defined to have one result, but it might really have none
+    // if we're not using CallingConv::AnyReg. Don't mistake the chain for a
+    // real definition.
+    NodeNumDefs = 0;
+    return;
+  }
   unsigned NRegDefs = SchedDAG->TII->get(Node->getMachineOpcode()).getNumDefs();
   // Some instructions define regs that are not represented in the selection DAG
   // (e.g. unused flags). See tMOVi8. Make sure we don't access past NumValues.