7.5 Conditions Inhibiting Inlining/IPA

This section lists conditions that inhibit the inlining of subroutines and functions, whether from a library or source file. Many constructs that prevent inlining will also stop or restrict IPA.

See Section 7.4.6 for other notes on the use of the -inline and -ipa command switches and directives.

Conditions that inhibit inlining are as follows:

• Dummy and actual arguments are mismatched in type or class.

• Missing dummy parameter.

• Missing actual parameter and the corresponding dummy parameter is an array.

• Actual parameter is a nonscalar expression (for example, A+B, where A and B are arrays).

• Number of actual parameters differs from the number of dummy parameters.

• The size of an array actual parameter differs from the array dummy parameter AND the arrays cannot be linearized.

• Subprogram is too long ( > 600 lines).

• Subprogram has a SAVE statement.

• Subprogram has variables that are live-on-entry, even if they are not in explicit SAVE statements.

• Subprogram has a DATA statement and DATA implies SAVE and the variable is live-on-entry.

• Calling routine and called routine have mismatched COMMON declarations.

• Called routine has EQUIVALENCE statements. (Some of these can be handled.)

• Called routine has NAMELIST statements.

• Called routine has dynamic arrays.

• CALL to be expanded has alternate return parameters.

• Subprogram to be inlined contains a CALL with a subroutine or function name as an argument.

• Subprogram contains unsubscripted array references in I/O statements.

• Subprogram to be inlined contains POINTER statements.