This patch adds asserting as_a <scalar_int_mode> conversions
to contexts in which the input is known to be a scalar integer mode.

In expand_divmod, op1 is always a scalar_int_mode if
op1_is_constant (but might not be otherwise).

In expand_binop, the patch reverses a < comparison in order to
avoid splitting a long line.

gcc/
2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

	* cfgexpand.c (convert_debug_memory_address): Use
	as_a <scalar_int_mode>.
	* combine.c (expand_compound_operation): Likewise.
	(make_extraction): Likewise.
	(change_zero_ext): Likewise.
	(simplify_comparison): Likewise.
	* cse.c (cse_insn): Likewise.
	* dwarf2out.c (minmax_loc_descriptor): Likewise.
	(mem_loc_descriptor): Likewise.
	(loc_descriptor): Likewise.
	* expmed.c (init_expmed_one_mode): Likewise.
	(synth_mult): Likewise.
	(emit_store_flag_1): Likewise.
	(expand_divmod): Likewise.  Use HWI_COMPUTABLE_MODE_P instead
	of a comparison with size.
	* expr.c (expand_assignment): Use as_a <scalar_int_mode>.
	(reduce_to_bit_field_precision): Likewise.
	* function.c (expand_function_end): Likewise.
	* internal-fn.c (expand_arith_overflow_result_store): Likewise.
	* loop-doloop.c (doloop_modify): Likewise.
	* optabs.c (expand_binop): Likewise.
	(expand_unop): Likewise.
	(expand_copysign_absneg): Likewise.
	(prepare_cmp_insn): Likewise.
	(maybe_legitimize_operand): Likewise.
	* recog.c (const_scalar_int_operand): Likewise.
	* rtlanal.c (get_address_mode): Likewise.
	* simplify-rtx.c (simplify_unary_operation_1): Likewise.
	(simplify_cond_clz_ctz): Likewise.
	* tree-nested.c (get_nl_goto_field): Likewise.
	* tree.c (build_vector_type_for_mode): Likewise.
	* var-tracking.c (use_narrower_mode): Likewise.

gcc/c-family/
2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

	* c-common.c (c_common_type_for_mode): Use as_a <scalar_int_mode>.

gcc/lto/
2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

	* lto-lang.c (lto_type_for_mode): Use as_a <scalar_int_mode>.

From-SVN: r251487