`FT` compilation error from `copy-zr-temp` flag

[blackgeorge-boom]

cd layout/npb/ft
make clean; make stackmaps-check -j10 OBJDUMP_FLAGS= OPT_LEVEL=-O1 EXPERIMENT_MODE=1 LLC_FLAGS_ARM64=-mattr=+copy-zr-temp

gives:

llc: /home/blackgeorge/llvm-project/llvm/lib/CodeGen/VirtRegMap.cpp:565: void {anonymous}::VirtRegRewriter::rewrite(): Assertion `PhysReg && "Invalid SubReg for physical register"' failed.
Stack dump:
0.      Program arguments: /home/blackgeorge/llvm-9/toolchain/bin/llc -function-sections -data-sections -relocation-model=pic --trap-unreachable -optimize-regalloc -fast-isel=false -disable-machine-cse -mattr=+copy-zr-temp -march=aarch64 -filetype=obj -o fft3d_aarch64_init.o fft3d_opt.ll 
1.      Running pass 'Function Pass Manager' on module 'fft3d_opt.ll'.
2.      Running pass 'Virtual Register Rewriter' on function '@fftXYZ'
/home/blackgeorge/llvm-9/toolchain/bin/llc(_ZN4llvm3sys15PrintStackTraceERNS_11raw_ostreamE+0x37)[0x5584428b70a5]
/home/blackgeorge/llvm-9/toolchain/bin/llc(+0x2d5213c)[0x5584428b713c]
/home/blackgeorge/llvm-9/toolchain/bin/llc(_ZN4llvm3sys17RunSignalHandlersEv+0x92)[0x5584428b4fd6]
/home/blackgeorge/llvm-9/toolchain/bin/llc(+0x2d51a2f)[0x5584428b6a2f]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x153c0)[0x7f49040613c0]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0xcb)[0x7f4903b0118b]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x12b)[0x7f4903ae0859]
/lib/x86_64-linux-gnu/libc.so.6(+0x25729)[0x7f4903ae0729]
/lib/x86_64-linux-gnu/libc.so.6(+0x36f36)[0x7f4903af1f36]
/home/blackgeorge/llvm-9/toolchain/bin/llc(+0x2222f37)[0x558441d87f37]
/home/blackgeorge/llvm-9/toolchain/bin/llc(+0x2221595)[0x558441d86595]
/home/blackgeorge/llvm-9/toolchain/bin/llc(_ZN4llvm19MachineFunctionPass13runOnFunctionERNS_8FunctionE+0x213)[0x558441ad03e3]
/home/blackgeorge/llvm-9/toolchain/bin/llc(_ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE+0x2c2)[0x558442007056]
/home/blackgeorge/llvm-9/toolchain/bin/llc(_ZN4llvm13FPPassManager11runOnModuleER
...