add loop labels

Author: gareth-nx

src/stdlib_selection.fypp

@@ -90,7 +90,7 @@ contains
               error stop "select must have 1 <= k <= size(a), and 1 <= left <= right <= size(a)";
           end if
 
-          do
+          searchk: do
               mid = l + ((r-l)/2_ip) ! Avoid (l+r)/2 which can cause overflow
 
               call medianOf3(a, l, mid, r)
@@ -105,7 +105,7 @@ contains
                 kth_smallest = a(k)
                 return
               end if
-          end do
+          end do searchk
 
           contains
               pure subroutine swap(a, b)
@@ -136,10 +136,10 @@ contains
                     do while (array(hi) > pivot)
                       hi=hi-1_ip
                     end do
-                    do while (lo <= hi )
-                       if(array(lo) > pivot) exit
+                    inner_lohi: do while (lo <= hi )
+                       if(array(lo) > pivot) exit inner_lohi
                       lo=lo+1_ip
-                    end do
+                    end do inner_lohi
                     if (lo <= hi) then
                       call swap(array(lo),array(hi))
                       lo=lo+1_ip
@@ -206,7 +206,7 @@ contains
               error stop "arg_select must have 1 <= k <= size(a), and 1 <= left <= right <= size(a)";
           end if
 
-          do
+          searchk: do
               mid = l + ((r-l)/2_ip) ! Avoid (l+r)/2 which can cause overflow
 
               call arg_medianOf3(a, indx, l, mid, r)
@@ -221,7 +221,7 @@ contains
                 kth_smallest = indx(k)
                 return
               end if
-          end do
+          end do searchk
 
           contains
               pure subroutine swap(a, b)
@@ -254,10 +254,10 @@ contains
                     do while (array(indx(hi)) > pivot)
                       hi=hi-1_ip
                     end do
-                    do while (lo <= hi )
-                      if(array(indx(lo)) > pivot) exit
+                    inner_lohi: do while (lo <= hi )
+                      if(array(indx(lo)) > pivot) exit inner_lohi
                       lo=lo+1_ip
-                    end do
+                    end do inner_lohi
                     if (lo <= hi) then
                       call swap(indx(lo),indx(hi))
                       lo=lo+1_ip