If you invoke the Intel® Fortran Compiler without specifying any compiler options, the default state of each option takes effect. The following tables summarize the options whose default status is ON as they are required for Intel Fortran Compiler default operation. The tables group the options by their functionality.
Per your application requirement, you can disable one or more options.
For the default states and values of all options, see the Compiler Options Quick Reference Alphabetical table. The table provides links to the sections describing the functionality of the options. If an option has a default value, such value is indicated. If an option includes an optional minus [-], this option is ON by default.
The following tables list all options that compiler uses for its default execution.
Default Option |
Description |
-72. |
-72,-80,-132 specifies the column length for fixed form source only. The compiler might issue a warning for non-numeric text beyond 72 for the -72 option. |
-align |
Analyzes and reorders memory layout for variables and arrays. |
-ansi |
-ansi[-] enables assumption of the program's ANSI conformance. |
-r4 |
Specifies the size of the real numbers to four bytes. |
-auto_scalar |
Makes scalar local variables AUTOMATIC. |
-dps |
Enables DEC* parameter statement recognition. |
-i4 |
-i{2|4|8} defines the default KIND for integer variables and constants in 2, 4, and 8 bytes. |
-lowercase |
Controls the case of routine names and external linker symbols to all lowercase characters. |
-pad |
Enables changing variable and array memory layout. |
-pc64, IA-32 only |
-pc{32|64|80} enables floating-point significand precision control as follows: -pc32 to 24-bit significand, -pc64 to 53-bit significand, and -pc80 to 64-bit significand. |
-save |
Saves all variables in static allocation. Disables |
-sfalign8 |
Aligns stack for functions
with
8 or 16 byte variables. |
-u |
Sets IMPLICIT NONE. |
-us |
Appends an underscore to external subroutine names. |
IA-32: /Zp4 |
-Zp{n} specifies alignment constraint for structures
on 1-, 2-, 4-, 8-, or 16-byte boundary. To disable, use |
Default Option |
Description |
-fp |
Disables the use of the ebp register in optimizations. |
-ip_no_inlining |
Disables full or partial inlining that would result from the -ip interprocedural optimizations. Requires -ip or -ipo. |
-IPF_fma, |
Enables the contraction of floating-point multiply and add/subtract operations into a single operation. |
-IPF_fp_speculationfast, Itanium compiler |
Sets the compiler to speculate on floating-point operations. -IPF_fp_speculationoff disables this optimization. |
-IPF_fltacc, Itaniumcompiler |
Enables the compiler to apply optimizations that affect floating-point accuracy. By default, the compiler may apply optimizations that affect floating-point accuracy. -IPF_fltacc- disables such optimizations. -IPF_fltacc- is effective when -mp is on. |
-ipo_obj, |
Forces the generation of real object files. Requires -ipo. |
-O, -O1, -O2 |
Optimize for maximum speed. |
-openmp_report1 |
Indicates loops, regions, and sections parallelized. |
-opt_report_levelmin |
Specifies the minimal level of the optimizations report. |
-par_report1 |
Indicates loops successfully auto-parallelized. |
-tpp6 |
Optimizes code for the Pentium Pro®, Pentium II, and Pentium III processors for IA-32 applications. |
-unroll |
-unroll[n]: omit n
to let the compiler decide whether to perform unrolling or not (default). |
-vec_report1 |
Indicates loops successfully vectorized. |
Default Option |
Description |
-falias |
Enables aliasing in program. |
-ffnalias |
Enables aliasing across functions. |
-fverbose-asm |
Produces assembly file with compiler comments including compiler version and options used. |
-fpp1 |
Enables CVF conditional and
# directives. |
-sox |
Enables saving of compiler options and version in the executable. For Itanium-based systems, accepted for compatibility only. |
Default Option |
Description |
-cerrs |
Enables errors and warning messages to be printed in a terse
format. To disable, use |
-w1 |
Displays warnings. |
To disable an option, use one of the following as applies:
Generally, to disable one, group or all options, use -O0 option. For example:
IA-32 applications:
prompt>ifc -O2 -O0 input_file(s)
Itanium-based applications:
prompt>efc -O2 -O0 input_file(s)
To disable options that include optional "-" shown as [-], use that option in the command line in this format: -option-.
To disable options that have {n} parameter, use n=0 version in this format: -option0.
To reset data type default options, you need to indicate a new option whch overrides the default setting. For example:
IA-32 applications:
prompt>ifc -i2 input_file(s)
Itanium-based applications:
prompt>efc -i2 input_file(s)
Option -i2 overrides default option -i4.