[15/77] Add scalar_int_mode

[15/77] Add scalar_int_mode

Similar to the previous scalar_float_mode patch, but for modes that
satisfy SCALAR_INT_MODE_P.  There are very many uses of scalar integers,
so this patch only makes a token change to the types of byte_mode,
word_mode, ptr_mode and rs6000_pmode.  The next patches in the series
gradually replace more uses.

The patch also removes and adds casts to some target-specific code
due to the new types of SImode, DImode and Pmode.

The as_a <scalar_int_mode> goes away in a later patch.

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

gcc/
	* config/powerpcspe/powerpcspe.h (rs6000_pmode): Change type from
	machine_mode to scalar_int_mode.
	* config/powerpcspe/powerpcspe.c (rs6000_pmode): Likewise.
	(rs6000_option_override_internal): Remove cast to int.
	* config/rs6000/rs6000.h (rs6000_pmode): Change type from
	machine_mode to scalar_int_mode.
	* config/rs6000/rs6000.c (rs6000_pmode): Likewise.
	(rs6000_option_override_internal): Remove cast to int.
	* config/s390/s390.h (Pmode): Remove cast to machine_mode.
	* config/epiphany/epiphany.h (RTX_OK_FOR_OFFSET_P): Add cast
	to machine_mode.
	* config/s390/s390.c (s390_expand_builtin): Likewise.
	* coretypes.h (scalar_int_mode): New type.
	(opt_scalar_int_mode): New typedef.
	* machmode.h (scalar_int_mode): New class.
	(scalar_int_mode::includes_p): New function.
	(byte_mode): Change type to scalar_int_mode.
	(word_mode): Likewise.
	(ptr_mode): Likewise.
	* emit-rtl.c (byte_mode): Likewise.
	(word_mode): Likewise.
	(ptr_mode): Likewise.
	(init_derived_machine_modes): Update accordingly.
	* genmodes.c (get_mode_class): Return scalar_int_mode for MODE_INT
	and MODE_PARTIAL_INT.
	* gdbhooks.py (build_pretty_printer): Handle scalar_int_mode and
	opt_scalar_int_mode.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r251467