Compiler options

This topic describes new or changed compiler options.

You can specify compiler options on the command line. You can also modify compiler behavior through directives embedded in your application source files. For detailed descriptions and usage information for XL Fortran compiler options, see the XL Fortran Compiler Reference.

-I
This option is extended to support submodules. You can use it to add a directory to the search path for submodule symbol (.smod) files.
-M, -qmakedep
This option produces a dependency output file containing targets suitable for inclusion in a description file for the make command.
-MF
This option is used to specify the name or location for the dependency output files that are generated by the -qmakedep or -M option.
-MT
This option is used to specify the target name of the object file in the make rule in the dependency output file that is generated by the -qmakedep or -M option.
-qarch
The option default is updated to pwr4. Suboptions denoting old hardware families are silently upgraded to newer architectures.
The following suboptions are added or updated:
-qarch=pwr7
This suboption produces object code containing instructions that run on the POWER7®, POWER7+™, or POWER8™ hardware platforms.
-qarch=pwr8
This suboption produces object code containing instructions that run on the POWER8 hardware platforms.
-qcheck
The following suboptions are added:
-qcheck=all
This suboption enables all suboptions.
-qcheck=bounds
This suboption checks each reference to an array, array section, or character substring to ensure that the reference stays within the defined bounds of the entity.
-qcheck=stackclobber
This suboption detects a certain type of stack corruption in your programs.
-qcheck=unset
This suboption checks for automatic variables that are used before they are set at run time.
-qdbgfmt=dwarf4
This suboption generates debugging information in DWARF 4 format.
-qfunctrace
This option is extended to support submodules.
-qhelp
This option displays the man page of the compiler.
-qinfo

The following suboptions are added :

-qinfo=HOSTASSOCiation
This suboption notifies you about entities that are accessed by host association.
-qinfo=mt
This suboption notifies you about potential places where synchronization is needed.
-qinfo=unset
This suboption detects automatic variables that are used before they are set, and flags them with informational messages at compile time.
-qmoddir
This option is extended to support submodules. You can use it to specify the location for any submodule (.smod) symbol files.
-qpath
This option specifies locations for complier components. You can specify a different path for each component.
-qpdf1=unique
This suboption creates a unique PDF file for each process during run time.
-qprefetch=dscr
This suboption helps to improve the runtime performance of your applications. You can specify a value for dscr depending on your system architecture.
-qsimd=auto
This suboption controls the autosimdization, which was performed by the deprecated -qhot=simd option.
-qtune
The option default is updated.
The following suboptions are added or updated:
-qtune=pwr7
This suboption specifies that optimizations are tuned for the POWER7 or POWER7+ hardware platforms.
-qtune=pwr8
This suboption specifies that optimizations are tuned for the POWER8 hardware platforms.
SMT suboptions
The new -qtune simultaneous multithreading (SMT) suboptions allow you to specify a target SMT to direct optimization for best performance in that mode.
-qunroll=n
This suboption hints to the compiler to unroll loops by a factor of n. If the loop has fewer than n iterations, it is fully unrolled.
-WL
This suboption specifies additional options for the IPA link step.