re PR tree-optimization/79737 (wrong code at -O2 and -O3 on x86_64-linux-gnu (in both 32-bit and 64-bit modes))

	PR tree-optimization/79737
	* gimple-ssa-store-merging.c (encode_tree_to_bitpos): If bitlen is
	a multiple of BITS_PER_UNIT and !BYTES_BIG_ENDIAN, clear
	tmpbuf[byte_size - 1].  Call natice_encode_expr with byte_size - 1
	instead of byte_size.  Formatting fix.
	(shift_bytes_in_array_right): Formatting fix.

	* gcc.c-torture/execute/pr79737-1.c: New test.
	* gcc.c-torture/execute/pr79737-2.c: New test.

From-SVN: r245795