Mangler does not generate C++ valid names with boolean-valued parameters

[simonbyrne]

I was looking into why some names where not being demangled in Nsight Systems: it looks like some of the mangled names cannot be demangled with cu++filt, or llvm-cxxfilt.

One particular case is when a boolean value is used as a parameter. For example:

julia> import GPUCompiler: mangle_sig

julia> struct XX{T} end

julia> m = mangle_sig(Tuple{typeof(sin), XX{true}})
"_Z3sin2XXILitrueEE"

julia> readchomp(`cu++filt $m`)
"_Z3sin2XXILitrueEE"

I also get similar results on my mac with c++filt on my Mac (which uses llvm-cxxfilt):

julia> readchomp(`c++filt -n $m`)
"_Z3sin2XXILitrueEE"

It does appear to work on Linux with c++filt (which uses GNU c++filt):

julia> readchomp(`c++filt -n $m`)
"sin(XX<true>)"