[6/77] Make GET_MODE_WIDER return an opt_mode

GET_MODE_WIDER previously returned VOIDmode if no wider mode existed.
That would cause problems with stricter mode classes, since VOIDmode
isn't for example a valid scalar integer or floating-point mode.
This patch instead makes it return a new opt_mode<T> class, which
holds either a T or nothing.

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

gcc/
	* coretypes.h (opt_mode): New class.
	* machmode.h (opt_mode): Likewise.
	(opt_mode::else_void): New function.
	(opt_mode::require): Likewise.
	(opt_mode::exists): Likewise.
	(GET_MODE_WIDER_MODE): Turn into a function and return an opt_mode.
	(GET_MODE_2XWIDER_MODE): Likewise.
	(mode_iterator::get_wider): Update accordingly.
	(mode_iterator::get_2xwider): Likewise.
	(mode_iterator::get_known_wider): Likewise, turning into a template.
	* combine.c (make_extraction): Update use of GET_MODE_WIDER_MODE,
	forcing a wider mode to exist.
	* config/cr16/cr16.h (LONG_REG_P): Likewise.
	* rtlanal.c (init_num_sign_bit_copies_in_rep): Likewise.
	* config/c6x/c6x.c (c6x_rtx_costs): Update use of
	GET_MODE_2XWIDER_MODE, forcing a wider mode to exist.
	* lower-subreg.c (init_lower_subreg): Likewise.
	* optabs-libfuncs.c (init_sync_libfuncs_1): Likewise, but not
	on the final iteration.
	* config/i386/i386.c (ix86_expand_set_or_movmem): Check whether
	a wider mode exists before asking for a move pattern.
	(get_mode_wider_vector): Update use of GET_MODE_WIDER_MODE,
	forcing a wider mode to exist.
	(expand_vselect_vconcat): Update use of GET_MODE_2XWIDER_MODE,
	returning false if no such mode exists.
	* config/ia64/ia64.c (expand_vselect_vconcat): Likewise.
	* config/mips/mips.c (mips_expand_vselect_vconcat): Likewise.
	* expmed.c (init_expmed_one_mode): Update use of GET_MODE_WIDER_MODE.
	Avoid checking for a MODE_INT if we already know the mode is not a
	SCALAR_INT_MODE_P.
	(extract_high_half): Update use of GET_MODE_WIDER_MODE,
	forcing a wider mode to exist.
	(expmed_mult_highpart_optab): Likewise.
	(expmed_mult_highpart): Likewise.
	* expr.c (expand_expr_real_2): Update use of GET_MODE_WIDER_MODE,
	using else_void.
	* lto-streamer-in.c (lto_input_mode_table): Likewise.
	* optabs-query.c (find_widening_optab_handler_and_mode): Likewise.
	* stor-layout.c (bit_field_mode_iterator::next_mode): Likewise.
	* internal-fn.c (expand_mul_overflow): Update use of
	GET_MODE_2XWIDER_MODE.
	* omp-low.c (omp_clause_aligned_alignment): Likewise.
	* tree-ssa-math-opts.c (convert_mult_to_widen): Update use of
	GET_MODE_WIDER_MODE.
	(convert_plusminus_to_widen): Likewise.
	* tree-switch-conversion.c (array_value_type): Likewise.
	* var-tracking.c (emit_note_insn_var_location): Likewise.
	* tree-vrp.c (simplify_float_conversion_using_ranges): Likewise.
	Return false inside rather than outside the loop if no wider mode
	exists
	* optabs.c (expand_binop): Update use of GET_MODE_WIDER_MODE
	and GET_MODE_2XWIDER_MODE
	(can_compare_p): Use else_void.
	* gdbhooks.py (OptMachineModePrinter): New class.
	(build_pretty_printer): Use it for opt_mode.

gcc/ada/
	* gcc-interface/decl.c (validate_size): Update use of
	GET_MODE_WIDER_MODE, forcing a wider mode to exist.

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

From-SVN: r251457

1 files changed, 10 insertions, 10 deletions

diff --git a/gcc/optabs.c b/gcc/optabs.c
index ce419d3..c6ad64b 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -1186,13 +1186,13 @@ expand_binop (machine_mode mode, optab binoptab, rtx op0, rtx op1,
      takes operands of this mode and makes a wider mode.  */
 
   if (binoptab == smul_optab
-      && GET_MODE_2XWIDER_MODE (mode) != VOIDmode
-      && (widening_optab_handler ((unsignedp ? umul_widen_optab
-					     : smul_widen_optab),
-				  GET_MODE_2XWIDER_MODE (mode), mode)
-	  != CODE_FOR_nothing))
+      && GET_MODE_2XWIDER_MODE (mode).exists (&wider_mode)
+      && (convert_optab_handler ((unsignedp
+				  ? umul_widen_optab
+				  : smul_widen_optab),
+				 wider_mode, mode) != CODE_FOR_nothing))
     {
-      temp = expand_binop (GET_MODE_2XWIDER_MODE (mode),
+      temp = expand_binop (wider_mode,
 			   unsignedp ? umul_widen_optab : smul_widen_optab,
 			   op0, op1, NULL_RTX, unsignedp, OPTAB_DIRECT);
 
@@ -1253,14 +1253,14 @@ expand_binop (machine_mode mode, optab binoptab, rtx op0, rtx op1,
       && methods != OPTAB_DIRECT && methods != OPTAB_LIB)
     FOR_EACH_WIDER_MODE (wider_mode, mode)
       {
+	machine_mode next_mode;
 	if (optab_handler (binoptab, wider_mode) != CODE_FOR_nothing
 	    || (binoptab == smul_optab
-		&& GET_MODE_WIDER_MODE (wider_mode) != VOIDmode
+		&& GET_MODE_WIDER_MODE (wider_mode).exists (&next_mode)
 		&& (find_widening_optab_handler ((unsignedp
 						  ? umul_widen_optab
 						  : smul_widen_optab),
-						 GET_MODE_WIDER_MODE (wider_mode),
-						 mode, 0)
+						 next_mode, mode, 0)
 		    != CODE_FOR_nothing)))
 	  {
 	    rtx xop0 = op0, xop1 = op1;
@@ -3702,7 +3702,7 @@ can_compare_p (enum rtx_code code, machine_mode mode,
 	  && optab_handler (cmov_optab, mode) != CODE_FOR_nothing)
 	return 1;
 
-      mode = GET_MODE_WIDER_MODE (mode);
+      mode = GET_MODE_WIDER_MODE (mode).else_void ();
       PUT_MODE (test, mode);
     }
   while (mode != VOIDmode);