(zero_extendhisi2): Rewrite to work if op0 == op1. Use
gen_lowpart in preparation code.
(extendqisi2, extendhisi2): Likewise.
(extendqihi2): Expand.
(restorehi): Rewrite for correctness, efficiency, and
clarity. Avoid generating insns involving truncate. Generate
needed pseudos in preparation statements.
(storehi): Likewise.
(storeinthi): Likewise.
(movhi): Call gen_storehi, gen_restorehi, gen_storeinthi according
their new definitions. Use force_reg to put address in register.
From-SVN: r2255
Use gen_lowpart to change mode of operand 0.
(storeinthi): Use match_operand for operand 0.
Change output code to reassign operand 0.
(truncsihi2, truncsiqi2, trunchiqi2): Remove these patterns.
From-SVN: r2057
