7.1.4 DO Loop Level

The qualifiers, /inline_looplevel=<n> [/inll] and /ipa_looplevel=<n> [/ipall] , set a minimum DO loop nest level for CALL/function reference expansion. The /inline_ looplevel and /ipa_looplevel qualifiers enable you to limit inlining and IPA to just routines that are referenced in nested loops, where the reduced call overhead or enhanced optimization will be multiplied.

The argument is defined from the most deeply nested leaf of the call tree. The default, 10, allows inlining (IPA) for the 10 deepest nest levels, for example:

 PROGRAM MAIN
  ..

   CALL A ---> SUBROUTINE A

 ..

    DO
     DO
       CALL B --> SUBROUTINE B
     ENDDO  DO

     ENDDO  DO
        CALL C ---> SUBROUTINE C

     ENDDO
    ENDDO

The CALL B is inside a doubly nested loop, and would be more profitable to expand than the CALL A . The CALL C is quadruply nested, so inlining C would yield the biggest gain of the three.

The argument is defined from the most deeply nested CALL or function reference:


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Command-Line Qualifiers