[Bug tree-optimization/26804] New: Alias Time explosion

["amacleod at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

Alias analysis is taking a long time now.

I seem to  have narrowed it down to this patch:

http://gcc.gnu.org/ml/gcc-patches/2006-01/msg00908.html




running cpgram.ii shows a regression:

before patch:

 tree alias analysis   :   2.49 ( 7%) usr   0.25 ( 5%) sys   6.13 ( 5%) wall   
4971 kB ( 1%) ggc
 TOTAL                 :  36.90             4.72           130.34            
467341 kB

after patch:

 tree alias analysis   :  59.00 (63%) usr   0.40 ( 7%) sys  70.43 (36%) wall   
4957 kB ( 1%) ggc
 TOTAL                 :  94.13             5.43           193.85            
468339 kB


on a 386 linux machine bootstrapped with checking disabled.

cpgram.ii needs to be compiled with -fpermissive -O2


-- 
           Summary: Alias Time explosion
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: amacleod at redhat dot com
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26804