[Bug target/59718] New: Behaviour of -mcpu documented incorrectly for ARM targets

["bogden at arm dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59718

            Bug ID: 59718
           Summary: Behaviour of -mcpu documented incorrectly for ARM
                    targets
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bogden at arm dot com

I am given to understand that the behaviour of the -mcpu option for both the
ARM and AArch64 targets is that it is a shorthand for specifying -march=foo
-mtune=bar, where bar is a CPU that implements foo.

However, the documentation for AArch64
(gcc-4.8.2/gcc/AArch64-Options.html#AArch64-Options) says that -mcpu is the
same as -march, except that it takes CPU names rather than architecture
versions.

http://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/ARM-Options.html#ARM-Options is
similar except that it seems to describe the correct behaviour in one specific
case.

These sections should be rewritten to correctly describe the behaviour of
-mcpu.