lazy execution optimization

[Sylvain Pion <Sylvain dot Pion at sophia dot inria dot fr>]

Let's consider the following function:

int f (double a, double b)
{
  double c;
  c = a+b;
  if (a > 0.0) return 0;
  if (c > 0.0) return 1;
  return 2;
}

I would like GCC to optimize it by computing "c" only after the first test,
just as if the code was:

int f (double a, double b)
{
  double c;
  if (a > 0.0) return 0;
  c = a+b;
  if (c > 0.0) return 1;
  return 2;
}

It seems 2.95.1 as well as the current CVS do not perform such an
optimization.

Would it be reasonnable and possible ?

-- 
Sylvain