re PR target/56564 (movdqa on possibly-8-byte-aligned struct with -O3)

re PR target/56564 (movdqa on possibly-8-byte-aligned struct with -O3)

	PR target/56564
	* varasm.c (align_variable): Don't use DATA_ALIGNMENT or
	CONSTANT_ALIGNMENT if !decl_binds_to_current_def_p (decl).
	Use DATA_ABI_ALIGNMENT for that case instead if defined.
	(get_variable_align): New function.
	(get_variable_section, emit_bss, emit_common,
	assemble_variable_contents, place_block_symbol): Use
	get_variable_align instead of DECL_ALIGN.
	(assemble_noswitch_variable): Add align argument, use it
	instead of DECL_ALIGN.
	(assemble_variable): Adjust caller.  Use get_variable_align
	instead of DECL_ALIGN.
	* config/i386/i386.h (DATA_ALIGNMENT): Adjust x86_data_alignment
	caller.
	(DATA_ABI_ALIGNMENT): Define.
	* config/i386/i386-protos.h (x86_data_alignment): Adjust prototype.
	* config/i386/i386.c (x86_data_alignment): Add opt argument.  If
	opt is false, only return the psABI mandated alignment increase.
	* config/c6x/c6x.h (DATA_ALIGNMENT): Renamed to...
	(DATA_ABI_ALIGNMENT): ... this.
	* config/mmix/mmix.h (DATA_ALIGNMENT): Renamed to...
	(DATA_ABI_ALIGNMENT): ... this.
	* config/mmix/mmix.c (mmix_data_alignment): Adjust function comment.
	* config/s390/s390.h (DATA_ALIGNMENT): Renamed to...
	(DATA_ABI_ALIGNMENT): ... this.
	* doc/tm.texi.in (DATA_ABI_ALIGNMENT): Document.
	* doc/tm.texi: Regenerated.

	* gcc.target/i386/pr56564-1.c: New test.
	* gcc.target/i386/pr56564-2.c: New test.
	* gcc.target/i386/pr56564-3.c: New test.
	* gcc.target/i386/pr56564-4.c: New test.
	* gcc.target/i386/avx256-unaligned-load-4.c: Add -fno-common.
	* gcc.target/i386/avx256-unaligned-store-1.c: Likewise.
	* gcc.target/i386/avx256-unaligned-store-3.c: Likewise.
	* gcc.target/i386/avx256-unaligned-store-4.c: Likewise.
	* gcc.target/i386/vect-sizes-1.c: Likewise.
	* gcc.target/i386/memcpy-1.c: Likewise.
	* gcc.dg/vect/costmodel/i386/costmodel-vect-31.c (tmp): Initialize.
	* gcc.dg/vect/costmodel/x86_64/costmodel-vect-31.c (tmp): Likewise.

From-SVN: r199898