[Bug tree-optimization/68550] New: [6 Regression] ICE: verify_gimple failed Error: missing PHI def

[Joost.VandeVondele at mat dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68550

            Bug ID: 68550
           Summary: [6 Regression] ICE: verify_gimple failed Error:
                    missing PHI def
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Joost.VandeVondele at mat dot ethz.ch
  Target Milestone: ---

graphite-triggered ICE in current trunk.

> cat bug.f90
  SUBROUTINE integrate_core_1(grid,coef_xyz,pol_x,pol_y,&
             pol_z,map,sphere_bounds,cmax,gridbounds)
    INTEGER, PARAMETER :: dp=8
    INTEGER, INTENT(IN)    :: sphere_bounds(*), cmax, &
                              map(-cmax:cmax,1:3), &
                              gridbounds(2,3)
    REAL(dp), INTENT(IN) :: grid(gridbounds(1,1):gridbounds(2,1), &
             gridbounds(1,2):gridbounds(2,2),&
             gridbounds(1,3):gridbounds(2,3))
    INTEGER, PARAMETER     :: lp = 1
    REAL(dp), INTENT(IN)   :: pol_x(0:lp,-cmax:cmax), &
                              pol_y(1:2,0:lp,-cmax:0), &
                              pol_z(1:2,0:lp,-cmax:0)
    REAL(dp), INTENT(OUT) :: coef_xyz(((lp+1)*(lp+2)*(lp+3))/6)
    INTEGER   :: i, ig, igmax, igmin, j, j2, &
                 jg, jg2, jgmin, k, k2, kg, &
                 kg2, kgmin, lxp, sci
    REAL(dp)  :: coef_x(4,0:lp), &
                 coef_xy(2,((lp+1)*(lp+2))/2), &
                 s(4)
    DO kg=kgmin,0
       DO jg=jgmin,0
          coef_x=0.0_dp
          DO ig=igmin,igmax
             DO lxp=0,lp
                coef_x(:,lxp)=coef_x(:,lxp)+s(:)*pol_x(lxp,ig)
             ENDDO
          END DO
             coef_xy(:,3)=coef_xy(:,3)+coef_x(3:4,0)*pol_y(2,1,jg)
       END DO
                coef_xyz(3)=coef_xyz(3)+coef_xy(1,3)*pol_z(1,0,kg)
    END DO
  END SUBROUTINE integrate_core_1

> gfortran -c -O2 -floop-nest-optimize  bug.f90
bug.f90:1:0:

   SUBROUTINE integrate_core_1(grid,coef_xyz,pol_x,pol_y,&


Error: missing PHI def
bug.f90:1:0: Error: missing PHI def
prephitmp_133 = PHI <(8), (16)>
bug.f90:1:0: internal compiler error: verify_gimple failed
0xbab969 verify_gimple_in_cfg(function*, bool)
        ../../gcc/gcc/tree-cfg.c:5082
0xa92b8c execute_function_todo
        ../../gcc/gcc/passes.c:1958
0xa9361b execute_todo
        ../../gcc/gcc/passes.c:2010
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

> gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/data/vjoost/gnu/gcc_trunk/install/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/data/vjoost/gnu/gcc_trunk/install
--enable-languages=c,c++,fortran --disable-multilib --enable-plugins
--enable-lto --disable-bootstrap
Thread model: posix
gcc version 6.0.0 20151126 (experimental) [trunk revision 230923] (GCC)