stack dump at -early-cse-memssa twice

Hello,

while invoking opt with all possible optimization pairs I stumbled over
a stack dump when doing -early-cse-memssa twice:

    $ clang -Xclang -disable-O0-optnone -S -o fannkuch7.ll -emit-llvm fannkuch7.c

  $ opt -S -o fannkuch7.ll -early-cse-memssa -early-cse-memssa fannkuch7.ll

Questions:
Is it illegal to call -early-cse-memssa twice?
Are there any other incompatible optimization orders?

Best,
HwJ

fannkuch7.c (1.86 KB)

I think it's flaw in the PassManager or something like that. Nothing
should prevent you from running -early-cse-memssa twice.