-qtune

Description

Specifies the architecture system for which the executable program is optimized.

Syntax

Read syntax diagramSkip visual syntax diagram                 .-pwr3---.
>>- -q--tune--=--+-auto---+------------------------------------><
                 +-403----+
                 +-601----+
                 +-602----+
                 +-603----+
                 +-604----+
                 +-p2sc---+
                 +-ppc----+
                 +-ppc970-+
                 +-pwr----+
                 +-pwr2---+
                 +-pwr2s--+
                 +-pwr4---+
                 +-pwr5---+
                 +-rs64a--+
                 +-rs64b--+
                 '-rs64c--'

where architecture suboptions are:

403 Produces object code optimized for the PowerPC 403(TM) processor.
601 Produces object code optimized for the PowerPC 601(R) processor.
602 Produces object code optimized for the PowerPC(R) 602 processor.
603 Produces object code optimized for the PowerPC 603(TM) processor.
604 Produces object code optimized for the PowerPC 604(TM) processor.
auto Produces object code optimized for the platfom on which it is compiled.
p2sc Produces object code optimized for the PowerPC P2SC processor.
ppc970 Produces object code optimized for the PowerPC 970 processor.
pwr Produces object code optimized for the POWER(TM) hardware platforms.
pwr2 Produces object code optimized for the POWER2(TM) hardware platforms.
pwr2s Produces object code optimized for the POWER2 hardware platforms, avoiding certain quadruple-precision instructions that would slow program performance.
pwr3 Produces object code optimized for the POWER3(TM) hardware platforms.
pwr4 Produces object code optimized for the POWER4(TM) hardware platforms.
pwr5 Produces object code optimized for the POWER5(TM) hardware platforms.
pwrx Produces object code optimized for the POWER2 hardware platforms (same as -qtune=pwr2).
rs64a Produces object code optimized for the RS64I processor.
rs64b Produces object code optimized for the RS64II processor.
rs64c Produces object code optimized for the RS64III processor.

See also #pragma options.

Default

The default setting of the -qtune option depends on the setting of the -qarch option.

If you specify -q32 or -q64 option without specifying -qarch setting, -qtune=pwr3 will be set as the default.

Default -qtune settings for specific -qarch settings are described in Acceptable compiler mode and process or architecture combinations.

Notes

You can use -qtune=suboption with -qarch=suboption.

Example

To specify that the executable program testing compiled from myprogram.C is to be optimized for a POWER hardware platform, enter:

xlc++ -o testing myprogram.C -qtune=pwr3

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