[Bug regression/51511] New: [4.6/4.7 regression] gcc.dg/pr45819.c fails on arm-linux-gnueabi due to PR50078+PR51466 fix

["mikpe at it dot uu.se" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51511

             Bug #: 51511
           Summary: [4.6/4.7 regression] gcc.dg/pr45819.c fails on
                    arm-linux-gnueabi due to PR50078+PR51466 fix
    Classification: Unclassified
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikpe@it.uu.se


The PR50078+PR51466 fix, r182157 on 4.6 branch, caused a test suite regression
on arm-linux-gnueabi:

+FAIL: gcc.dg/pr45819.c (test for excess errors)

because the compiler now emits the following warning:

pr45819.c: In function 'ehci_hub_control':
pr45819.c:16:10: warning: mis-aligned access used for structure member
[-fstrict-volatile-bitfields]
pr45819.c:16:10: note: when a volatile object spans multiple type-sized
locations, the compiler must choose between using a single mis-aligned access
to preserve the volatility, or using multiple aligned accesses to avoid runtime
faults; this code may fail at runtime if the hardware does not allow this
access

I believe the warning is correct, so perhaps the warning should just be
suppressed
in pr45819.c with -w.  gcc-4.7-20111210 has the same issue.