[Bug middle-end/43654] New: Very long compile time with -O2 -floop-block

[zsojka at seznam dot cz]

Tested revisions:
r157965 - fail (~140s)
r153685 - crash
4.4 r157895 - OK (~0.2s)

Executed on a 1.6GHz CPU, CLooG-PPL 0.15.8, PPL 0.10.2:
$ /mnt/svn/gcc-trunk/binary-157965-lto/bin/gcc -O2 -floop-block testcase.c
-ftime-report -c

Execution times (seconds)
 Graphite loop transforms: 135.75 (100%) usr   0.88 (100%) sys 137.88 (100%)
wall      26 kB ( 1%) ggc
 Graphite data dep analysis:   0.02 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%)
wall       0 kB ( 0%) ggc
 Graphite code generation:   0.05 ( 0%) usr   0.00 ( 0%) sys   0.06 ( 0%) wall 
    59 kB ( 3%) ggc
 tree iv optimization  :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall   
 151 kB ( 8%) ggc
 tree STMT verifier    :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall   
   0 kB ( 0%) ggc
 loop invariant motion :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall   
   5 kB ( 0%) ggc
 branch prediction     :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall   
   2 kB ( 0%) ggc
 reload                :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall   
   4 kB ( 0%) ggc
 TOTAL                 : 135.87             0.88           137.99              
1961 kB
Extra diagnostic checks enabled; compiler may run slowly.
Configure with --enable-checking=release to disable checks.

Disabling checking doesn't help.


-- 
           Summary: Very long compile time with -O2 -floop-block
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: zsojka at seznam dot cz
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43654