SImode -> DImode optimizations

[Richard Henderson]

On Fri, Feb 22, 2002 at 03:32:38PM +1030, Alan Modra wrote:
> What's the correct way to let gcc know that SImode insn patterns
> leave the high part of a reg in a known state?

Create additional patterns that also contain the zero_extend.  I.e.

  (set (match_operand:DI 0 "gpc_reg_operand" "=r")
       (zero_extend:DI
	 (rotate:SI (match_operand:SI 1 "gpc_reg_operand" "r")
		    (match_operand:SI 2 "reg_or_cint_operand" "ri"))))


r~