C2: assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc

(synopsis is provisional, feel free to change it or close as duplicate of known bug)

Attached Fuzzer test fails like:

$ ../build/linux-x86_64-server-fastdebug/images/jdk/bin/java -Xmx512m -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:+StressCCP -Xcomp -XX:CompileOnly=Test -XX:-TieredCompilation -XX:StressSeed=84360828 Test

# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/shade/trunks/jdk/src/hotspot/share/opto/chaitin.cpp:1670), pid=3439441, tid=3439454
# assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc

Bisection shows it started with JDK-8273612, but that might only be because the profiling info had changed a bit.