poly_int: tree constants

This patch adds a tree representation for poly_ints.  Unlike the
rtx version, the coefficients are INTEGER_CSTs rather than plain
integers, so that we can easily access them as poly_widest_ints
and poly_offset_ints.

The patch also adjusts some places that previously
relied on "constant" meaning "INTEGER_CST".  It also makes
sure that the TYPE_SIZE agrees with the TYPE_SIZE_UNIT for
vector booleans, given the existing:

	/* Several boolean vector elements may fit in a single unit.  */
	if (VECTOR_BOOLEAN_TYPE_P (type)
	    && type->type_common.mode != BLKmode)
	  TYPE_SIZE_UNIT (type)
	    = size_int (GET_MODE_SIZE (type->type_common.mode));
	else
	  TYPE_SIZE_UNIT (type) = int_const_binop (MULT_EXPR,
						   TYPE_SIZE_UNIT (innertype),
						   size_int (nunits));

2017-12-20  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* doc/generic.texi (POLY_INT_CST): Document.
	* tree.def (POLY_INT_CST): New tree code.
	* treestruct.def (TS_POLY_INT_CST): New tree layout.
	* tree-core.h (tree_poly_int_cst): New struct.
	(tree_node): Add a poly_int_cst field.
	* tree.h (POLY_INT_CST_P, POLY_INT_CST_COEFF): New macros.
	(wide_int_to_tree, force_fit_type): Take a poly_wide_int_ref
	instead of a wide_int_ref.
	(build_int_cst, build_int_cst_type): Take a poly_int64 instead
	of a HOST_WIDE_INT.
	(build_int_cstu, build_array_type_nelts): Take a poly_uint64
	instead of an unsigned HOST_WIDE_INT.
	(build_poly_int_cst, tree_fits_poly_int64_p, tree_fits_poly_uint64_p)
	(ptrdiff_tree_p): Declare.
	(tree_to_poly_int64, tree_to_poly_uint64): Likewise.  Provide
	extern inline implementations if the target doesn't use POLY_INT_CST.
	(poly_int_tree_p): New function.
	(wi::unextended_tree): New class.
	(wi::int_traits <unextended_tree>): New override.
	(wi::extended_tree): Add a default constructor.
	(wi::extended_tree::get_tree): New function.
	(wi::widest_extended_tree, wi::offset_extended_tree): New typedefs.
	(wi::tree_to_widest_ref, wi::tree_to_offset_ref): Use them.
	(wi::tree_to_poly_widest_ref, wi::tree_to_poly_offset_ref)
	(wi::tree_to_poly_wide_ref): New typedefs.
	(wi::ints_for): Provide overloads for extended_tree and
	unextended_tree.
	(poly_int_cst_value, wi::to_poly_widest, wi::to_poly_offset)
	(wi::to_wide): New functions.
	(wi::fits_to_boolean_p, wi::fits_to_tree_p): Handle poly_ints.
	* tree.c (poly_int_cst_hasher): New struct.
	(poly_int_cst_hash_table): New variable.
	(tree_node_structure_for_code, tree_code_size, simple_cst_equal)
	(valid_constant_size_p, add_expr, drop_tree_overflow): Handle
	POLY_INT_CST.
	(initialize_tree_contains_struct): Handle TS_POLY_INT_CST.
	(init_ttree): Initialize poly_int_cst_hash_table.
	(build_int_cst, build_int_cst_type, build_invariant_address): Take
	a poly_int64 instead of a HOST_WIDE_INT.
	(build_int_cstu, build_array_type_nelts): Take a poly_uint64
	instead of an unsigned HOST_WIDE_INT.
	(wide_int_to_tree): Rename to...
	(wide_int_to_tree_1): ...this.
	(build_new_poly_int_cst, build_poly_int_cst): New functions.
	(force_fit_type): Take a poly_wide_int_ref instead of a wide_int_ref.
	(wide_int_to_tree): New function that takes a poly_wide_int_ref.
	(ptrdiff_tree_p, tree_to_poly_int64, tree_to_poly_uint64)
	(tree_fits_poly_int64_p, tree_fits_poly_uint64_p): New functions.
	* lto-streamer-out.c (DFS::DFS_write_tree_body, hash_tree): Handle
	TS_POLY_INT_CST.
	* tree-streamer-in.c (lto_input_ts_poly_tree_pointers): Likewise.
	(streamer_read_tree_body): Likewise.
	* tree-streamer-out.c (write_ts_poly_tree_pointers): Likewise.
	(streamer_write_tree_body): Likewise.
	* tree-streamer.c (streamer_check_handled_ts_structures): Likewise.
	* asan.c (asan_protect_global): Require the size to be an INTEGER_CST.
	* cfgexpand.c (expand_debug_expr): Handle POLY_INT_CST.
	* expr.c (expand_expr_real_1, const_vector_from_tree): Likewise.
	* gimple-expr.h (is_gimple_constant): Likewise.
	* gimplify.c (maybe_with_size_expr): Likewise.
	* print-tree.c (print_node): Likewise.
	* tree-data-ref.c (data_ref_compare_tree): Likewise.
	* tree-pretty-print.c (dump_generic_node): Likewise.
	* tree-ssa-address.c (addr_for_mem_ref): Likewise.
	* tree-vect-data-refs.c (dr_group_sort_cmp): Likewise.
	* tree-vrp.c (compare_values_warnv): Likewise.
	* tree-ssa-loop-ivopts.c (determine_base_object, constant_multiple_of)
	(get_loop_invariant_expr, add_candidate_1, get_computation_aff_1)
	(force_expr_to_var_cost): Likewise.
	* tree-ssa-loop.c (for_each_index): Likewise.
	* fold-const.h (build_invariant_address, size_int_kind): Take a
	poly_int64 instead of a HOST_WIDE_INT.
	* fold-const.c (fold_negate_expr_1, const_binop, const_unop)
	(fold_convert_const, multiple_of_p, fold_negate_const): Handle
	POLY_INT_CST.
	(size_binop_loc): Likewise.  Allow int_const_binop_1 to fail.
	(int_const_binop_2): New function, split out from...
	(int_const_binop_1): ...here.  Handle POLY_INT_CST.
	(size_int_kind): Take a poly_int64 instead of a HOST_WIDE_INT.
	* expmed.c (make_tree): Handle CONST_POLY_INT_P.
	* gimple-ssa-strength-reduction.c (slsr_process_add)
	(slsr_process_mul): Check for INTEGER_CSTs before using them
	as candidates.
	* stor-layout.c (bits_from_bytes): New function.
	(bit_from_pos): Use it.
	(layout_type): Likewise.  For vectors, multiply the TYPE_SIZE_UNIT
	by BITS_PER_UNIT to get the TYPE_SIZE.
	* tree-cfg.c (verify_expr, verify_types_in_gimple_reference): Allow
	MEM_REF and TARGET_MEM_REF offsets to be a POLY_INT_CST.

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

From-SVN: r255863

1 files changed, 28 insertions, 7 deletions

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 6706219..0056d75 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -841,6 +841,28 @@ start_record_layout (tree t)
   return rli;
 }
 
+/* Fold sizetype value X to bitsizetype, given that X represents a type
+   size or offset.  */
+
+static tree
+bits_from_bytes (tree x)
+{
+  if (POLY_INT_CST_P (x))
+    /* The runtime calculation isn't allowed to overflow sizetype;
+       increasing the runtime values must always increase the size
+       or offset of the object.  This means that the object imposes
+       a maximum value on the runtime parameters, but we don't record
+       what that is.  */
+    return build_poly_int_cst
+      (bitsizetype,
+       poly_wide_int::from (poly_int_cst_value (x),
+			    TYPE_PRECISION (bitsizetype),
+			    TYPE_SIGN (TREE_TYPE (x))));
+  x = fold_convert (bitsizetype, x);
+  gcc_checking_assert (x);
+  return x;
+}
+
 /* Return the combined bit position for the byte offset OFFSET and the
    bit position BITPOS.
 
@@ -854,8 +876,7 @@ tree
 bit_from_pos (tree offset, tree bitpos)
 {
   return size_binop (PLUS_EXPR, bitpos,
-		     size_binop (MULT_EXPR,
-				 fold_convert (bitsizetype, offset),
+		     size_binop (MULT_EXPR, bits_from_bytes (offset),
 				 bitsize_unit_node));
 }
 
@@ -2272,9 +2293,10 @@ layout_type (tree type)
 	  TYPE_SIZE_UNIT (type) = int_const_binop (MULT_EXPR,
 						   TYPE_SIZE_UNIT (innertype),
 						   size_int (nunits));
-	TYPE_SIZE (type) = int_const_binop (MULT_EXPR,
-					    TYPE_SIZE (innertype),
-					    bitsize_int (nunits));
+	TYPE_SIZE (type) = int_const_binop
+	  (MULT_EXPR,
+	   bits_from_bytes (TYPE_SIZE_UNIT (type)),
+	   bitsize_int (BITS_PER_UNIT));
 
 	/* For vector types, we do not default to the mode's alignment.
 	   Instead, query a target hook, defaulting to natural alignment.
@@ -2387,8 +2409,7 @@ layout_type (tree type)
 	      length = size_zero_node;
 
 	    TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
-					   fold_convert (bitsizetype,
-							 length));
+					   bits_from_bytes (length));
 
 	    /* If we know the size of the element, calculate the total size
 	       directly, rather than do some division thing below.  This