re PR middle-end/27567 (__builtin_memcpy generates redundant stores/moves.)

re PR middle-end/27567 (__builtin_memcpy generates redundant stores/moves.)

	PR middle-end/27567
	* builtins.c (fold_builtin_memcpy, fold_builtin_memmove): Remove.
	(fold_builtin_mempcpy): Rename to...
	(fold_builtin_memory_op): ... this.  Optimize one element copy
	into an assignment.
	(fold_builtin_memset, fold_builtin_bzero, fold_builtin_bcopy): New
	functions.
	(expand_builtin_strcpy, expand_builtin_strncpy): Handle COMPOUND_EXPR.
	(expand_builtin_memcpy, expand_builtin_mempcpy,
	expand_builtin_memmove): Likewise.  Use fold_builtin_memory_op.
	(fold_builtin_1): Handle BUILT_IN_MEMSET, BUILT_IN_BZERO and
	BUILT_IN_BCOPY.  Use fold_builtin_memory_op for
	BUILT_IN_MEM{CPY,PCPY,MOVE}.

From-SVN: r116656