[C--] bool and bits1

Hi,

My front-end takes a very simple strategy.  Instead of only simplifying 
complex expression wherever it's necessary, it translates all complex 
expressions to three address forms.  This brings me to the bool and 
bits1 issue.

In C--, the type of predicate and logic expressions is bool, and there 
is no bool type in C-- grammar.  That said, it's not possible to 
allocate temporary variables of bool to simplify complicate 
predicate/logic expressions to three address forms.  But C-- does allow 
you to allocate variables of bits1 and convert the C-- expressions of 
bool to bits1.  If you want to compute the conjunction of two sub 
predicates whose results are now stored in two bits1 variables, then you 
have to convert it back to bool.  The type conversions between bool and 
bits1 seem redundant.

My questions are:

1. Why there is no bool type in the C-- grammar, but the semantics of 
C-- has bool type? allowing bool type would eliminate the above 
redundant  type conversions.

2. I guess most of the use of bits1 is like the above case.  Any 
exception?  Why bool and bits1 are not equivalent types?

Thanks,
Ning
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