profiler_report Subroutine

   subroutine profiler_report(title, root_region)
      !! Print profiling report
      !! If root_region is specified, percentages are relative to that region
      character(len=*), intent(in), optional :: title
      character(len=*), intent(in), optional :: root_region
      integer :: i, j, root_idx, n_print, tmp_idx
      integer :: sorted_idx(MAX_REGIONS)
      real(dp) :: total_time, pct
      character(len=256) :: line

      if (state%num_regions == 0) return

      root_idx = -1
      if (present(root_region)) then
         do i = 1, state%num_regions
            if (trim(state%regions(i)%name) == trim(root_region)) then
               root_idx = i
               exit
            end if
         end do
      end if

      if (root_idx > 0) then
         total_time = state%regions(root_idx)%total_time
      else
         total_time = 0.0_dp
         do i = 1, state%num_regions
            total_time = total_time + state%regions(i)%total_time
         end do
      end if

      n_print = 0
      do i = 1, state%num_regions
         if (i /= root_idx .and. .not. state%regions(i)%nvtx_only) then
            n_print = n_print + 1
            sorted_idx(n_print) = i
         end if
      end do

      ! Sort by time descending (insertion sort)
      do i = 2, n_print
         tmp_idx = sorted_idx(i)
         j = i - 1
         ! Guard the sorted_idx(j) read with a SEPARATE bounds check: Fortran
         ! does not short-circuit `.and.`, so a combined
         ! `do while (j >= 1 .and. ...sorted_idx(j)...)` reads sorted_idx(0)
         ! when j reaches 0 (OOB — aborts under -fcheck=bounds).
         do
            if (j < 1) exit
            if (state%regions(sorted_idx(j))%total_time >= &
                state%regions(tmp_idx)%total_time) exit
            sorted_idx(j + 1) = sorted_idx(j)
            j = j - 1
         end do
         sorted_idx(j + 1) = tmp_idx
      end do

      call logger%info("")
      call logger%info("============================================================")
      if (present(title)) then
         call logger%info("Profiler Report: "//trim(title))
      else
         call logger%info("Profiler Report")
      end if
      call logger%info("============================================================")
      call logger%info("  Region                          Time (s)    Calls    %    ")
      call logger%info("------------------------------------------------------------")

      do i = 1, n_print
         j = sorted_idx(i)
         if (total_time > 0.0_dp) then
            pct = 100.0_dp*state%regions(j)%total_time/total_time
         else
            pct = 0.0_dp
         end if
         write (line, "(A,A32,F12.6,I8,F8.1)") "  ", &
            state%regions(j)%name, &
            state%regions(j)%total_time, &
            state%regions(j)%call_count, &
            pct
         call logger%info(trim(line))
      end do

      call logger%info("------------------------------------------------------------")
      write (line, "(A,F12.6)") "  Total:                        ", total_time
      call logger%info(trim(line))
      call logger%info("============================================================")

#ifdef USE_NVTX
      call logger%info("  (NVTX enabled - use Nsight Systems for GPU timeline)")
#else
      call logger%info("  (NVTX disabled - compile with -DRDB_ENABLE_NVTX to enable)")
#endif
   end subroutine profiler_report