Setting Compiler Options - Fortran Levels

Use this pane area to optimize code at different levels, select the language level, and select a source form.

Code Optimization
Press mouse button 1 to see the various options associated with the Optimization field. To optimize code during compilation, select one of these option buttons:

none Performs no optimization on the generated code. Choosing this option is the same as entering the -qNOOPTimize option on the command line.

2 Performs a set of optimizations intended to offer improved performance without an unreasonable increase in time or storage required for compilation. Choosing this option is the same as entering the -O, -O2, -qOPTimize, or -qOPTimize=2 options on the command line.

3 Performs additional optimizations that are memory intensive, compile-time intensive, or both. Use this option if you want your program to run faster. Choosing this option is the same as entering the -O3 or -qOPTimize=3 options on the command line.

3 strict Turns off the aggressive optimizations of the -O3 option that may alter the semantics of your program. Selecting this option turns off the following -O3 optimizations:

Performing code motion and scheduling on computations, such as loads and floating-point computations that may trigger an exception.

Relaxing conformance to IEEE rules.

Reassociating floating-point expressions.

Choosing this option is the same as entering the -O3 -qstrict or -qOPTimize=3 -qstrict options on the command line.

4 This option provides the same optimizations as -O3, except that it also:

Sets the -qipa option

Sets the -qarch and -qtune options to the architecture of the compiling machine

Language Levels
To select a Language level (-qlanglvl) when using Fortran, press mouse button 1 on the Fortran field, then select one of these option buttons:

extended Accepts the full Fortran 95 language plus all XL Fortran extensions, effectively turning off language-level checking. This is the default.

90std Accepts the language specified by the ISO Fortran 90 standard, and reports anything else as an error.

90pure The same as 90std, except that it reports errors for any obsolescent Fortran 90 features used.

95std Accepts the language specified by the ISO Fortran 95 standard, and reports anything else as an error.

95pure The same as 95std, except that it reports errors for any obsolescent Fortran 95 features used.

77std Accepts the language specified by the ANSI F77 standard, the same as the obsolete -qfips options, and reports anything else as an error.

Source Forms
To select a source form when using Fortran, press mouse button 1 on the Source Form field, then select one of these options:

Use default Indicates that the input source program is in the default form. Default forms are:

-qfixed=72 For the xlf, xlhpf, and f77 commands.

-qfree=f90 For the xlf90, xlf95, xlhpf90, xlhpf95, f90, and f95 commands.

F90 free Indicates that the source code is in Fortran 90 free form (-qfree=f90).

Fixed Format Indicates that the input source program is in fixed form (-qfixed).

Setting Compiler Options - Fortran
Setting Compiler Options - Fortran Compilers
Setting Compiler Options - Fortran Flags
Setting Compiler Options - Fortran Include Directories

none	Performs no optimization on the generated code. Choosing this option is the same as entering the -qNOOPTimize option on the command line.
2	Performs a set of optimizations intended to offer improved performance without an unreasonable increase in time or storage required for compilation. Choosing this option is the same as entering the -O, -O2, -qOPTimize, or -qOPTimize=2 options on the command line.
3	Performs additional optimizations that are memory intensive, compile-time intensive, or both. Use this option if you want your program to run faster. Choosing this option is the same as entering the -O3 or -qOPTimize=3 options on the command line.
3 strict	Turns off the aggressive optimizations of the -O3 option that may alter the semantics of your program. Selecting this option turns off the following -O3 optimizations: Performing code motion and scheduling on computations, such as loads and floating-point computations that may trigger an exception. Relaxing conformance to IEEE rules. Reassociating floating-point expressions. Choosing this option is the same as entering the -O3 -qstrict or -qOPTimize=3 -qstrict options on the command line.
4	This option provides the same optimizations as -O3, except that it also: Sets the -qipa option Sets the -qarch and -qtune options to the architecture of the compiling machine

extended	Accepts the full Fortran 95 language plus all XL Fortran extensions, effectively turning off language-level checking. This is the default.
90std	Accepts the language specified by the ISO Fortran 90 standard, and reports anything else as an error.
90pure	The same as 90std, except that it reports errors for any obsolescent Fortran 90 features used.
95std	Accepts the language specified by the ISO Fortran 95 standard, and reports anything else as an error.
95pure	The same as 95std, except that it reports errors for any obsolescent Fortran 95 features used.
77std	Accepts the language specified by the ANSI F77 standard, the same as the obsolete -qfips options, and reports anything else as an error.