Visible to Intel only — GUID: GUID-37B3BC17-F282-4FC8-8666-F49D0B4B3702
Visible to Intel only — GUID: GUID-37B3BC17-F282-4FC8-8666-F49D0B4B3702
General Compiler Directives
Compiler directives are specially formatted comments in the source file which provide information to the compiler. Some directives, such as line length or conditional compilation directives provide the compiler information which is used in interpreting the source file.
Other directives, such as optimization directives provide hints or suggestions to the compiler, which, in some cases, may be ignored or overridden by the compiler based on the heuristics of the optimizer and/or code generator.
You do not need to specify a compiler option to enable general directives. If the directive is ignored by the compiler, no diagnostic message is issued.
The following general compiler directives are available:
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Specifies an alternate external name to be used when referring to external subprograms.
-
Provides heuristic information to the compiler optimizer.
-
Specifies that an entity in memory is aligned.
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Specifies properties for data objects and procedures.
-
Enables or disables loop blocking for the immediately following nested DO loops.
-
Generates or disables warnings for variables that have been used but not declared.
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Defines (or undefines) a symbolic variable whose existence (or value) can be tested during conditional compilation.
-
Suggests a location at which a DO loop may be split.
-
Sets the line length for fixed-form source code.
-
Enables (or disables) the compiler to allow generation of fused multiply-add (FMA) instructions, also known as floating-point contractions.
-
Specifies free-format or fixed-format source code.
-
Specifies an identifier for an object module.
-
Specifies a conditional compilation construct.
-
Tell the compiler to perform the specified inlining on routines within statements or DO loops.
-
Specifies the default integer kind.
-
Assists the compiler's dependence analysis of iterative DO loops.
-
Specifies the typical trip count for a DO loop; this assists the optimizer.
-
Specifies a character string to be sent to the standard output device during the first compiler pass.
-
Prevents a loop from fusing with adjacent loops.
-
Specifies a library search path in an object file.
-
Enables or disables optimizations for the program unit.
-
Affects data alignment and warnings about data alignment.
-
Specifies the memory alignment of derived-type items.
-
Facilitates or prevents auto-parallelization by assisting the compiler's dependence analysis of the immediately following DO loop. This feature is only available for ifort.
-
Enables or disables hint to the compiler to prefetch data from memory.
-
Modifies certain characteristics of a common block.
-
Specifies the default real kind.
-
Requires and controls SIMD vectorization of loops. This feature is only available for ifort.
-
Disables or enables language features not found in the language standard specified on the command line.
-
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.
-
Overrides default heuristics for vectorization of DO loops.
Product and Performance Information |
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Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex. Notice revision #20201201 |