array index of '-16' indexes before the beginning of the array

[Ryan Stone]

On Sun, Nov 27, 2011 at 6:42 PM, Andriy Gapon <avg at freebsd.org> wrote:
>
> Looks like clang has found a real issue here:
> /usr/src/sys/x86/x86/local_apic.c:311:2: warning: array index of '-16' indexes
> before the beginning of the array [-Warray-bounds]
>        lapics[apic_id].la_ioint_irqs[IDT_DTRACE_RET - APIC_IO_INTS] =
> IRQ_DTRACE_RET;
>
> IDT_DTRACE_RET (0x20) indeed seems to be less than APIC_IO_INTS.

Uh-oh, I appear to have broken this in r227290.  I'll try to figure
out what's actually supposed to be done here.