poly_int: PUSH_ROUNDING

PUSH_ROUNDING is difficult to convert to a hook since there is still
a lot of conditional code based on it.  It isn't clear that a direct
conversion with checks for null hooks is the right thing to do.

Rather than untangle that, this patch converts all implementations
that do something to out-of-line functions that have the same
interface as a hook would have.  This should at least help towards
any future hook conversion.

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* config/cr16/cr16-protos.h (cr16_push_rounding): Declare.
	* config/cr16/cr16.h (PUSH_ROUNDING): Move implementation to...
	* config/cr16/cr16.c (cr16_push_rounding): ...this new function.
	* config/h8300/h8300-protos.h (h8300_push_rounding): Declare.
	* config/h8300/h8300.h (PUSH_ROUNDING): Move implementation to...
	* config/h8300/h8300.c (h8300_push_rounding): ...this new function.
	* config/i386/i386-protos.h (ix86_push_rounding): Declare.
	* config/i386/i386.h (PUSH_ROUNDING): Move implementation to...
	* config/i386/i386.c (ix86_push_rounding): ...this new function.
	* config/m32c/m32c-protos.h (m32c_push_rounding): Take and return
	a poly_int64.
	* config/m32c/m32c.c (m32c_push_rounding): Likewise.
	* config/m68k/m68k-protos.h (m68k_push_rounding): Declare.
	* config/m68k/m68k.h (PUSH_ROUNDING): Move implementation to...
	* config/m68k/m68k.c (m68k_push_rounding): ...this new function.
	* config/pdp11/pdp11-protos.h (pdp11_push_rounding): Declare.
	* config/pdp11/pdp11.h (PUSH_ROUNDING): Move implementation to...
	* config/pdp11/pdp11.c (pdp11_push_rounding): ...this new function.
	* config/stormy16/stormy16-protos.h (xstormy16_push_rounding): Declare.
	* config/stormy16/stormy16.h (PUSH_ROUNDING): Move implementation to...
	* config/stormy16/stormy16.c (xstormy16_push_rounding): ...this new
	function.
	* expr.c (emit_move_resolve_push): Treat the input and result
	of PUSH_ROUNDING as a poly_int64.
	(emit_move_complex_push, emit_single_push_insn_1): Likewise.
	(emit_push_insn): Likewise.
	* lra-eliminations.c (mark_not_eliminable): Likewise.
	* recog.c (push_operand): Likewise.
	* reload1.c (elimination_effects): Likewise.
	* rtlanal.c (nonzero_bits1): Likewise.
	* calls.c (store_one_arg): Likewise.  Require the padding to be
	known at compile time.

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

From-SVN: r256155