poly_int: GET_MODE_PRECISION

This patch changes GET_MODE_PRECISION from an unsigned short
to a poly_uint16.

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

gcc/
	* machmode.h (mode_precision): Change from unsigned short to
	poly_uint16_pod.
	(mode_to_precision): Return a poly_uint16 rather than an unsigned
	short.
	(GET_MODE_PRECISION): Return a constant if ONLY_FIXED_SIZE_MODES,
	or if measurement_type is not polynomial.
	(HWI_COMPUTABLE_MODE_P): Turn into a function.  Optimize the case
	in which the mode is already known to be a scalar_int_mode.
	* genmodes.c (emit_mode_precision): Change the type of mode_precision
	from unsigned short to poly_uint16_pod.  Use ZERO_COEFFS for the
	initializer.
	* lto-streamer-in.c (lto_input_mode_table): Use bp_unpack_poly_value
	for GET_MODE_PRECISION.
	* lto-streamer-out.c (lto_write_mode_table): Use bp_pack_poly_value
	for GET_MODE_PRECISION.
	* combine.c (update_rsp_from_reg_equal): Treat GET_MODE_PRECISION
	as polynomial.
	(try_combine, find_split_point, combine_simplify_rtx): Likewise.
	(expand_field_assignment, make_extraction): Likewise.
	(make_compound_operation_int, record_dead_and_set_regs_1): Likewise.
	(get_last_value): Likewise.
	* convert.c (convert_to_integer_1): Likewise.
	* cse.c (cse_insn): Likewise.
	* expr.c (expand_expr_real_1): Likewise.
	* lra-constraints.c (simplify_operand_subreg): Likewise.
	* optabs-query.c (can_atomic_load_p): Likewise.
	* optabs.c (expand_atomic_load): Likewise.
	(expand_atomic_store): Likewise.
	* ree.c (combine_reaching_defs): Likewise.
	* rtl.h (partial_subreg_p, paradoxical_subreg_p): Likewise.
	* rtlanal.c (nonzero_bits1, lsb_bitfield_op_p): Likewise.
	* tree.h (type_has_mode_precision_p): Likewise.
	* ubsan.c (instrument_si_overflow): Likewise.

gcc/ada/
	* gcc-interface/misc.c (enumerate_modes): Treat GET_MODE_PRECISION
	as polynomial.

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

From-SVN: r256198

1 files changed, 9 insertions, 5 deletions

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index 33a0980..54b14d8 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -4431,6 +4431,7 @@ nonzero_bits1 (const_rtx x, scalar_int_mode mode, const_rtx known_x,
   unsigned HOST_WIDE_INT inner_nz;
   enum rtx_code code;
   machine_mode inner_mode;
+  unsigned int inner_width;
   scalar_int_mode xmode;
 
   unsigned int mode_width = GET_MODE_PRECISION (mode);
@@ -4735,8 +4736,9 @@ nonzero_bits1 (const_rtx x, scalar_int_mode mode, const_rtx known_x,
 	 machines, we can compute this from which bits of the inner
 	 object might be nonzero.  */
       inner_mode = GET_MODE (SUBREG_REG (x));
-      if (GET_MODE_PRECISION (inner_mode) <= BITS_PER_WORD
-	  && GET_MODE_PRECISION (inner_mode) <= HOST_BITS_PER_WIDE_INT)
+      if (GET_MODE_PRECISION (inner_mode).is_constant (&inner_width)
+	  && inner_width <= BITS_PER_WORD
+	  && inner_width <= HOST_BITS_PER_WIDE_INT)
 	{
 	  nonzero &= cached_nonzero_bits (SUBREG_REG (x), mode,
 					  known_x, known_mode, known_ret);
@@ -4752,8 +4754,9 @@ nonzero_bits1 (const_rtx x, scalar_int_mode mode, const_rtx known_x,
 		   ? val_signbit_known_set_p (inner_mode, nonzero)
 		   : extend_op != ZERO_EXTEND)
 	       || (!MEM_P (SUBREG_REG (x)) && !REG_P (SUBREG_REG (x))))
-	      && xmode_width > GET_MODE_PRECISION (inner_mode))
-	    nonzero |= (GET_MODE_MASK (xmode) & ~GET_MODE_MASK (inner_mode));
+	      && xmode_width > inner_width)
+	    nonzero
+	      |= (GET_MODE_MASK (GET_MODE (x)) & ~GET_MODE_MASK (inner_mode));
 	}
       break;
 
@@ -6078,8 +6081,9 @@ lsb_bitfield_op_p (rtx x)
       machine_mode mode = GET_MODE (XEXP (x, 0));
       HOST_WIDE_INT len = INTVAL (XEXP (x, 1));
       HOST_WIDE_INT pos = INTVAL (XEXP (x, 2));
+      poly_int64 remaining_bits = GET_MODE_PRECISION (mode) - len;
 
-      return (pos == (BITS_BIG_ENDIAN ? GET_MODE_PRECISION (mode) - len : 0));
+      return known_eq (pos, BITS_BIG_ENDIAN ? remaining_bits : 0);
     }
   return false;
 }