[Bug middle-end/17520] [4.0 regression] Huge compile time for C code

[sebastian dot pop at cri dot ensmp dot fr]

------- Additional Comments From sebastian dot pop at cri dot ensmp dot fr  2004-09-27 19:25 -------
Subject: Re:  [regression] Huge compile time for C code

I'm testing the following patch for speeding up the analyzer when there are 
numerous branches.  In gdb the time consumed by the analyzer dropped down by 
some significant amount of time.  I will post tomorow a proper patch if tests 
pass.

*** tree-scalar-evolution.c.~2.7.~	Fri Sep 17 11:14:09 2004
--- tree-scalar-evolution.c	Mon Sep 27 21:07:55 2004
*************** follow_ssa_edge_in_condition_phi (struct
*** 1398,1403 ****
--- 1398,1407 ----
  
    for (i = 1; i < PHI_NUM_ARGS (condition_phi); i++)
      {
+       /* Quickly give up when one of the branches is not known.  */
+       if (*evolution_of_loop == chrec_dont_know)
+ 	return true;
+ 
        if (!follow_ssa_edge_in_condition_phi_branch (i, loop, condition_phi,
  						    halting_phi,
  						    &evolution_of_branch,


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17520