topic This appears related to the in Intel® Fortran Compiler

Complex Matrix Assign Crashes in IFORT 16.0.3

John_Y_ — Wed, 15 Jun 2016 20:23:41 GMT

Hi,

Attached is a simple test case that crashes on a complex matrix assign in ifort 16.0.3. It works with all previous ifort versions I have used. The crash occurs when using the cmplx intrinsic and does not occur when not using the intrinsic. For example,

zz = cmplx(0._db,0._db,db) ! db defined in test file

crashes but

zz = 0._db ! db defined in test file

does not. My compile line is

ifort -traceback testZ8.F90

Thanks,

John

Thank you for the report and

Kevin_D_Intel — Wed, 15 Jun 2016 21:25:03 GMT

Thank you for the report and reproducer John. We'll look into this.

This appears related to the

Kevin_D_Intel — Fri, 17 Jun 2016 16:24:06 GMT

This appears related to the creation of array stack temporaries. The program runs with pre-16.0 compilers without any aid and runs with 16.0 compilers with the aid of either -heap-arrays or elevating the shell stack limit (i.e. ulimit –s unlimited).

I need to consult others whether the changed behavior was anticipated with 16.0. I'll update after learning more.

For convenience I included your test case below.

!======================================================================
program test
  implicit none

  integer, parameter :: db = kind(1.0d0)
  integer, parameter :: sg = kind(1.0)

  integer, parameter :: stdout = 6

  ! local variables
  integer :: itmp, i, ierr, m

  complex(db), allocatable :: zz(:,:)
  complex(sg), allocatable :: cc(:,:)

  m = 5868

  allocate(zz(m,m),stat=ierr)
  write(stdout,*) 'IERR: ', ierr
  allocate(cc(m,m),stat=ierr)
  write(stdout,*) 'IERR: ', ierr

  zz = 0._db ! This line ok
  zz = cmplx(0._db,0._db,db) ! This line crashes

  cc = 0._sg ! This line ok
  cc = cmplx(0._sg,0._sg,sg) ! This line crashes

  deallocate(zz,cc)

end program test

Kevin,

John_Y_ — Mon, 20 Jun 2016 12:06:12 GMT

Kevin,

Using "-heap-arrays" is a simple enough workaround. It's interesting the behavior changed though.

Thanks,

John

In version 15, the compiler

Steven_L_Intel1 — Mon, 20 Jun 2016 12:45:11 GMT

In version 15, the compiler did a simple element-by-element initialization in a loop. In version 16 it created an array temp for the whole initialized array and copied it - this triggered the stack overflow. In the upcoming version 17, it generates a vectorized loop to more efficiently set the values and doesn't use a temp.