Preservation of signedness flag on attribute values inconsistent

[povik]

Version

a8a65db

On which OS did this happen?

macOS

Reproduction Steps

read_rtlil <<EOF
attribute \a 32's00000000000000000000000000000100
attribute \b 32'00000000000000000000000000000100
attribute \c 5's00100
attribute \d 5'00100
module \top
end
EOF
write_rtlil /tmp/save.il
design -reset
read_rtlil /tmp/save.il
write_rtlil /tmp/save.il
design -reset
read_rtlil /tmp/save.il
dump

Expected Behavior

Values of a and b are distinguishable

Actual Behavior

autoidx 1

attribute \d 5'00100
attribute \c 5's00100
attribute \b 4
attribute \a 4
module \top
end

Values for c and d are distinguishable, not so for a and b

This is due to the autoint branch in RTLIL_BACKEND::dump_const