Don't create SSA names until in SSA form

Don't create SSA names until in SSA form

An upcoming patch adds a fold from hypot(x,x) to fabs(x)*sqrt(2).
This is unusual in that it could trigger in the gimplifier but would
require new SSA names to be created.  This patch makes sure that we
use the usual:

	  if (gimple_in_ssa_p (cfun))
	    res = make_ssa_name (type);
	  else
	    res = create_tmp_reg (type);

formula to cope with cases where we're not yet in SSA form.

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* gimple-match-head.c (maybe_push_res_to_seq): Use create_tmp_reg
	instead of make_ssa_name if not yet in SSA form.

From-SVN: r229406