[PATCH/AARCH64] Emit brk #0 for __builtin_trap

[Andrew Pinski <andrew dot pinski at caviumnetworks dot com>]

Hi all,
  This patch implements the trap pattern for the AARCH64 back-end.  I
used the "brk #0" instruction as that is the breakpoint instruction
that GDB uses.  I looked at what other targets did when the
instruction set did not have a trap instruction and found that using
the breakpoint instruction was a common theme between them if there
was not explicit defined undefined instruction to use.

OK?  Build and tested on aarch64-elf with no regressions.  Also built
a full aarch64-linux-gnu toolchain including glibc.

Thanks,
Andrew Pinski

ChangeLog:

* config/aarch64/aarch64.md (trap): New pattern.

Attachment: fixbuiltintrap.diff.txt
Description: Text document