General Compiler Directives

Intel® Fortran provides several general-purpose compiler directives to perform tasks during compilation. You do not need to specify a compiler option to enable general directives.

The following general compiler directives are available:

• ALIAS

  Specifies an alternate external name to be used when referring to external subprograms.

• ASSUME

  Provides heuristic information to the compiler optimizer.

• ASSUME_ALIGNED

  Specifies that an entity in memory is aligned.

• ATTRIBUTES

  Specifies properties for data objects and procedures.

• BLOCK_LOOP and NOBLOCK_LOOP

  Enables or disables loop blocking for the immediately following nested DO loops.

• DECLARE and NODECLARE

  Generates or disables warnings for variables that have been used but not declared.

• DEFINE and UNDEFINE

  Defines (or undefines) a symbolic variable whose existence (or value) can be tested during conditional compilation.

• DISTRIBUTE POINT

  Suggests a location at which a DO loop may be split.

• FIXEDFORMLINESIZE

  Sets the line length for fixed-form source code.

• FMA and NOFMA

  Enables (or disables) the compiler to allow generation of fused multiply-add (FMA) instructions, also known as floating-point contractions.

• FREEFORM and NOFREEFORM

  Specifies free-format or fixed-format source code.

• IDENT

  Specifies an identifier for an object module.

• IF and IF DEFINED

  Specifies a conditional compilation construct.

• INLINE, FORCEINLINE, NOINLINE

  Tell the compiler to perform the specified inlining on routines within statements or DO loops.

• INTEGER

  Specifies the default integer kind.

• IVDEP

  Assists the compiler's dependence analysis of iterative DO loops.

• LOOP COUNT

  Specifies the typical trip count for a DO loop; this assists the optimizer.

• MESSAGE

  Specifies a character string to be sent to the standard output device during the first compiler pass.

• NOFUSION

  Prevents a loop from fusing with adjacent loops.

• OBJCOMMENT

  Specifies a library search path in an object file.

• OPTIMIZE and NOOPTIMIZE

  Enables or disables optimizations for the program unit.

• OPTIONS

  Affects data alignment and warnings about data alignment.

• PACK

  Specifies the memory alignment of derived-type items.

• PARALLEL and NOPARALLEL

  Facilitates or prevents auto-parallelization by assisting the compiler's dependence analysis of theimmediately following DO loop.

• PREFETCH and NOPREFETCH

  Enables or disables hint to the compiler to prefetch data from memory.

• PSECT

  Modifies certain characteristics of a common block.

• REAL

  Specifies the default real kind.

• SIMD

  Requires and controls SIMD vectorization of loops.

• STRICT and NOSTRICT

  Disables or enables language features not found in the language standard specified on the command line.

• UNROLL and NOUNROLL

  Tells the compiler's optimizer how many times to unroll a DO loop or disables the unrolling of a DO loop.

• UNROLL_AND_JAM and NOUNROLL_AND_JAM

  Enables or disables loop unrolling and jamming.

• VECTOR and NOVECTOR

  Overrides default heuristics for vectorization of DO loops.