[Bug target/58869] New: switch -mcu=cortex-a7 conflicts with -march=armv7-a switch

[Bug target/58869] New: switch -mcu=cortex-a7 conflicts with -march=armv7-a switch

[wwfiney at hotmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58869

            Bug ID: 58869
           Summary: switch -mcu=cortex-a7 conflicts with -march=armv7-a
                    switch
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: wwfiney at hotmail dot com

When I compile code for cortex-a7, gcc reported a warning:
cc1: warning: switch -mcu=cortex-a7 conflicts with -march=armv7-a switch
[enabled by default]
But cortex-a7 IS armv7-a architecture.
So how can I set this switch?

[Bug target/58869] switch -mcu=cortex-a7 conflicts with -march=armv7-a switch

[rearnsha at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58869

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |WORKSFORME

--- Comment #1 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
If you specify -mcpu, you don't need to also specify the architecture; the
compiler can work that out from the CPU.

At a technical level, Cortex-A7 implements the ARMv7ve variant of ARMv7, which
is why you get conflict messages (v7ve having the integer divide instructions),
the diagnostic is telling you that the architecture derived from the CPU option
is at variance with that coming from the -march option.

If you really want to generate strict ARMv7 code that is tuned for cortex-a7,
then use -march=armv7-a -mtune=cortex-a7.