constraints.md (U): Adjust comment.

constraints.md (U): Adjust comment.

	* config/sparc/constraints.md (U): Adjust comment.
	* config/sparc/sparc.md (lra): New attribute.
	(enabled): For base instructions, if the lra attribute is set,
	return 1 if it is in keeping with TARGET_LRA.
	(*movdi_insn_sp32): Add lra attribute for alternatives mentioning U
	constraint and duplicate them with U replaced by r.
	(*movdf_insn_sp32): Likewise.
	(*mov<VM64:mode>_insn_sp32): Likewise.
	(*movtf_insn_sp32): Remove alternatives mentioning U constraint.

From-SVN: r243221