Discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html
In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.
llvm-svn: 323922
If the register from the copy from exec was spilled,
the copy before the spill was deleted leaving a spill
of undefined register verifier error and miscompiling.
Check for other use instructions of the copy register.
llvm-svn: 318132
Yaxun Liu