[Bug tree-optimization/27872] New: Internal compiler error in verify_loop_structure

["canqun at nudt dot edu dot cn" <gcc-bugzilla at gcc dot gnu dot org>]

This testcase will cause an internel error when compiled with options "-O3
-fprefetch-loop-arrays" on IA-64 + Linux.

      SUBROUTINE EBJFT()
      dimension  nmw(140)

      if(k.eq.0) goto 10
      go to 30
  10  continue

      do 20 l=1, 140
  20    nmw(l)= 0.0D0

  30  continue
      go to (10)lsn

      do 40 j=1, 140
        nmwj=nmw(j)
  40  continue
      write(*,*) nmwj

      end

The error message is:

prefetch-err.f: In function â??ebjftâ??
prefetch-err.f:3: error: edge from 50 to 36 should be marked irreducible
prefetch-err.f:3: internal compiler error: in verify_loop_structure, at
cfgloop.c:1268
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: Internal compiler error in verify_loop_structure
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: canqun at nudt dot edu dot cn
 GCC build triplet: ia64-unkown-linux
  GCC host triplet: ia64-unkown-linux
GCC target triplet: ia64-unkown-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27872