Context dependent expression simplification

2014-01-14 Thread 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

Re: Context dependent expression simplification

2014-01-14 Thread Jakub Jelinek 
On Tue, Jan 14, 2014 at 01:40:36PM +, Paulo Matos wrote:
 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)?

VRP should handle this (of course at the GIMPLE level) performs context
dependent optimizations through it's edge assertions.

Jakub

RE: Context dependent expression simplification

2014-01-14 Thread Paulo Matos 
 -Original Message-
 From: Jakub Jelinek [mailto:ja...@redhat.com]
 Sent: 14 January 2014 13:45
 To: Paulo Matos
 Cc: gcc@gcc.gnu.org
 Subject: Re: Context dependent expression simplification
 
 On Tue, Jan 14, 2014 at 01:40:36PM +, Paulo Matos wrote:
  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)?
 
 VRP should handle this (of course at the GIMPLE level) performs context
 dependent optimizations through it's edge assertions.

I need to do this during loop_doloop to simplify infinite conditons.
Might have to implement something to do this at RTL level then.

Paulo Matos

 
   Jakub