[Bug target/21397] New: -march selects wrong arm_tune flags

["trauscher at loytec dot com" <gcc-bugzilla at gcc dot gnu dot org>]

When using -march, wrong tuning flags are selected.
E.g., -march=armv4t selects 'tune_flags' for arm600, instead of
arm7tdmi (or similar). The error is in arm_override_options().

When "-march" is given, (sel - all_architectures) is calculated.
In contrast, "-mcpu" calculates (sel -  all_cores). This
array index is stored in 'arm_tune' (arm.c:791)

In arm.c:909 tune_flags are always taken from all_cores so 
that the calculated index references the wrong array when
using "-march"

tune_flags = all_cores[(int)arm_tune].flags;

-- 
           Summary: -march selects wrong arm_tune flags
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: trauscher at loytec dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i386-linux
GCC target triplet: arm-*-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21397