Add knowledge of phi-def and phi-kill valnos to MachineVerifier's predecessor
valno verification. The "Different value live out of predecessor" check is
incorrect in the case of phi-def valnos, so just skip that check for phi-def
valnos and instead check that all of the valnos for predecessors have phi-kill.
Fixes PR8863.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122581 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineVerifier.cpp b/lib/CodeGen/MachineVerifier.cpp
index d5dda48..0c29969 100644
--- a/lib/CodeGen/MachineVerifier.cpp
+++ b/lib/CodeGen/MachineVerifier.cpp
@@ -1146,7 +1146,23 @@
             *OS << "Valno #" << VNI->id << " live into BB#" << MFI->getNumber()
                 << '@' << LiveInts->getMBBStartIdx(MFI) << ", not live at "
                 << PEnd << " in " << LI << '\n';
-          } else if (PVNI != VNI) {
+            continue;
+          }
+
+          if (VNI->isPHIDef() && VNI->def == LiveInts->getMBBStartIdx(MFI)) {
+            if (!PVNI->hasPHIKill()) {
+              report("Value live out of predecessor doesn't have PHIKill", MF);
+              *OS << "Valno #" << PVNI->id << " live out of BB#"
+                  << (*PI)->getNumber() << '@' << PEnd
+                  << " doesn't have PHIKill, but Valno #" << VNI->id
+                  << " is PHIDef and defined at the beginning of BB#"
+                  << MFI->getNumber() << '@' << LiveInts->getMBBStartIdx(MFI)
+                  << " in " << LI << '\n';
+            }
+            continue;
+          }
+
+          if (PVNI != VNI) {
             report("Different value live out of predecessor", *PI);
             *OS << "Valno #" << PVNI->id << " live out of BB#"
                 << (*PI)->getNumber() << '@' << PEnd