07a40b33e5
The outlined taskloop preheader still used the original function's
casted step value when computing the canonical loop trip count. When
lb/ub/step were defined outside the taskloop body, the outlined function
ended up referring to an instruction from another function, which
crashed LLVM IR verification and finalization.
Reload the task step from the outlined task shareds, alongside lb and
ub, and use that value for the trip-count division. Update the MLIR
taskloop checks and add a regression for outer-scope variable bounds.
Fortran reproducer:
```
subroutine test(lb, ub, step)
integer :: i, lb, ub, step
!$omp taskloop
do i=lb,ub,step
call do_something(i)
enddo
!$omp end taskloop
end subroutine
```
Assisted-by: codex
Multi-Level Intermediate Representation
See https://mlir.llvm.org/ for more information.