Can I avoid "shift count is negative" warning? (involves template parameter)

["Phil Endecott" <spam_from_gcc_help@xxxxxxxxxxxx>]

Dear Experts,

template <int a>
int shift (int b)
{
  return (a>0) ? b>>a : b<<-a;
}

int f()
{
  return shift<1>(1);
  return shift<-1>(1);
}


$ g++ -W -c shiftwarn.cc
shiftwarn.cc: In function â??int shift(int) [with int a = 1]â??:
shiftwarn.cc:11:   instantiated from here
shiftwarn.cc:5: warning: left shift count is negative
shiftwarn.cc: In function â??int shift(int) [with int a = -0x00000000000000001]â??:
shiftwarn.cc:12:   instantiated from here
shiftwarn.cc:5: warning: right shift count is negative



Of course, the shift count is only negative in the branch of the the ?: 
that isn't used.

I get the same warning if I use if-then-else rather than ?:.  If 'a' is 
a regular function parameter rather than a template parameter, or if it 
is a constant, I don't get any warnings.

Is there any way to avoid this?  Do you consider it a bug?

This is g++ 4.1.2.

Many thanks for any suggestions.

Phil.

p.s. I've just noticed that it doesn't warn about having two return statements...