[AArch64][4.8] Backport Cortex-A53 erratum 835769 workaround

	* config/aarch64/aarch64.opt (mfix-cortex-a53-835769): New option.
	* config/aarch64/aarch64.h (ADJUST_INSN_LENGTH): Define.
	(FINAL_PRESCAN_INSN): Likewise.
	* config/aarch64/aarch64.h (is_mem_p): New function.
	(has_memory_op): Likewise.
	(aarch64_prev_real_insn): Likewise.
	(is_madd_op): Likewise.
	(dep_between_memop_and_curr): Likewise.
	(aarch64_madd_needs_nop): Likewise.
	(aarch64_final_prescan_insn): Likewise.
	* doc/invoke.texi (Document new option).



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_8-branch@216664 138bc75d-0d04-0410-961f-82ee72b054a4
[AArch64] Backport --enable-fix-cortex-a53-835769 configure option

	* config.gcc (aarch64*-*-*): Define TARGET_FIX_ERR_A53_835769_DEFAULT
	if asked.
	* configure.ac: Add --enable-fix-cortex-a53-835769 option.
	* configure: Regenerate.
	* config/aarch64/aarch64.c (aarch64_override_options): Handle
	TARGET_FIX_ERR_A53_835769_DEFAULT.
	* config/aarch64/aarch64.opt (mfix-cortex-a53-835769): Set Init value
	to 2.
	* doc/install.texi: Document --enable-fix-cortex-a53-835769 option.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_8-branch@216665 138bc75d-0d04-0410-961f-82ee72b054a4