The GAS assembler supports the ".set bopt" directive but according
to the sources it doesn't do anything. It's supposed to optimize
branches by filling the delay slot of a branch with it's target.
This patch teaches the MIPS asm parser to accept both and warn in
the case of 'bopt' that the bopt directive is unsupported.
This resolves PR/31841.
Thanks to Sean Bruno for reporting the issue!
llvm-svn: 293798
Simon Dardis