Summary:
While debugging another issue, I noticed that Mips currently specifies that the
count leading zero builtins are undefined when the input is zero. The
architecture specifications say that the clz and dclz instructions write 32 or
64 respectively when given zero.
This doesn't fix any bugs that I'm aware of but it may improve optimisation in
some cases.
Differential Revision: http://reviews.llvm.org/D4431
llvm-svn: 212618
Daniel Sanders