re PR tree-optimization/83521 (ICE: verify_gimple failed (error: invalid operand in unary operation))

	PR tree-optimization/83521
	* tree-ssa-phiopt.c (factor_out_conditional_conversion): Use
	gimple_build_assign without code on result of
	fold_build1 (VIEW_CONVERT_EXPR, ...), as it might not create
	a VIEW_CONVERT_EXPR.

	* gcc.dg/pr83521.c: New test.

From-SVN: r255952