5.5.1 /aggressive, /ag, (/noaggressive), /nag

This qualifier takes the following options:

• /aggressive=a tells KAP to pad COMMON blocks to avoid cache line collisions. This form of optimization is safe when the following conditions are satisfied:

  • All COMMON blocks are visible to KAP as it processes the source file.

  • If the same COMMON block has two different layouts, the different layouts do not pass data between them.

  • There are no bounds violations. This means that no adjustable arrays are being referenced outside their declared bounds.

  • There are no equivalences involving the common block variables.

  Most Fortran programs satisfy these conditions, so enabling this form of optimization can yield significant performance gains.

• /aggressive=b adjusts the leading dimensions of arrays in COMMON blocks away from a power of 2 if the arrays are not used as actual arguments to any of your subprograms.

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  Note

  You should use /aggressive=b only if the conditions for using /aggressive=a are satisfied and no array in any common block is passed as an actual argument to a function or subroutine.

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  This transformation should be used only if the performance of the program will not be degraded by changing the leading dimensions of arrays in COMMON blocks. It is most commonly used in combination with option a , as in /aggressive=ab .

• /aggressive=c allows inlining of routines that contain static (SAVE or DATA) variables by promoting these variables to members of a COMMON block introduced into the program.

  If the original program has DATA statements referring to some of the static variables, these DATA statements will now refer to members of the introduced COMMON block. Although most compilers support DATA statements that refer to elments of COMMON blocks, there may be some that do not. Therefore, this option should be used with care.

• /aggressive=d enables the compiler to do better optimization by allowing the assumption that those routines not processed by the compiler are side-effect free and cannot call routines processed by the compiler.

  This option enhances the abilities of interprocedural analysis and inlining to optimize the input program.

To explicitly disable these options, specify /noaggressive .

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