Context dependent expression simplification

[Paulo Matos]

Hello,

Before I start to write code to reinvent the wheel, I would like to know if 
there's something already out there to do context dependent expression 
simplification.
What I need is to simplify an expression at a given point in a BB.

For example:

  bb2:
   r1 <- 2
   if r2 != 0 goto bb3 else bb4   
  bb3:
   r3 <- r2 << 1
   goto bb4
  bb4:
   ...
   ...
   if ... goto bb4 else bb5

Is there any way already implemented to find the value of (and (plus r1 r3) 
(const_int 1)) at the end of bb4 and simplify it to (const_int 0)?

Cheers,

Paulo Matos