C2: assert(i >= req() || i == 0 || is_Region() || is_Phi()) with -XX:+VerifyGraphEdges

# Internal Error (open/src/hotspot/share/opto/node.cpp:2126), pid=16800, tid=16843
# assert(i >= req() || i == 0 || is_Region() || is_Phi()) failed: only regions or phis have null data edges

Current CompileTask:
C2: 1450 626 s 4 java.lang.StringBuffer::append (13 bytes)

Stack: [0x00007f47b1b92000,0x00007f47b1c93000], sp=0x00007f47b1c8fb20, free space=1014k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x11f7c43] Node::verify_edges(Unique_Node_List&)+0x173
V [libjvm.so+0x11f7d80] Node::verify_edges(Unique_Node_List&)+0x2b0
V [libjvm.so+0x11f7d80] Node::verify_edges(Unique_Node_List&)+0x2b0
V [libjvm.so+0x11f7d80] Node::verify_edges(Unique_Node_List&)+0x2b0
V [libjvm.so+0x85bfa4] Compile::verify_graph_edges(bool) [clone .part.366]+0x174
V [libjvm.so+0x874b74] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool, DirectiveSet*)+0x16b4

Reproduces with:
$ java -XX:+VerifyGraphEdges -jar dacapo-9.12-bach.jar avrora fop h2 jython luindex lusearch pmd sunflow xalan