1 /* A class for building vector tree constants.
2    Copyright (C) 2017-2018 Free Software Foundation, Inc.
3 
4 This file is part of GCC.
5 
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10 
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 for more details.
15 
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3.  If not see
18 <http://www.gnu.org/licenses/>.  */
19 
20 #ifndef GCC_TREE_VECTOR_BUILDER_H
21 #define GCC_TREE_VECTOR_BUILDER_H
22 
23 #include "vector-builder.h"
24 
25 /* This class is used to build VECTOR_CSTs from a sequence of elements.
26    See vector_builder for more details.  */
27 class tree_vector_builder : public vector_builder<tree, tree_vector_builder>
28 {
29   typedef vector_builder<tree, tree_vector_builder> parent;
30   friend class vector_builder<tree, tree_vector_builder>;
31 
32 public:
33   tree_vector_builder () : m_type (0) {}
34   tree_vector_builder (tree, unsigned int, unsigned int);
35   tree build ();
36 
37   tree type () const { return m_type; }
38 
39   void new_vector (tree, unsigned int, unsigned int);
40   bool new_unary_operation (tree, tree, bool);
41   bool new_binary_operation (tree, tree, tree, bool);
42 
43   static unsigned int binary_encoded_nelts (tree, tree);
44 
45 private:
46   bool equal_p (const_tree, const_tree) const;
47   bool allow_steps_p () const;
48   bool integral_p (const_tree) const;
49   wide_int step (const_tree, const_tree) const;
50   tree apply_step (tree, unsigned int, const wide_int &) const;
51   bool can_elide_p (const_tree) const;
52   void note_representative (tree *, tree);
53 
54   tree m_type;
55 };
56 
57 /* Create a new builder for a vector of type TYPE.  Initially encode the
58    value as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements
59    each.  */
60 
61 inline
62 tree_vector_builder::tree_vector_builder (tree type, unsigned int npatterns,
63 					  unsigned int nelts_per_pattern)
64 {
65   new_vector (type, npatterns, nelts_per_pattern);
66 }
67 
68 /* Start building a new vector of type TYPE.  Initially encode the value
69    as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.  */
70 
71 inline void
72 tree_vector_builder::new_vector (tree type, unsigned int npatterns,
73 				 unsigned int nelts_per_pattern)
74 {
75   m_type = type;
76   parent::new_vector (TYPE_VECTOR_SUBPARTS (type), npatterns,
77 		      nelts_per_pattern);
78 }
79 
80 /* Return true if elements I1 and I2 are equal.  */
81 
82 inline bool
83 tree_vector_builder::equal_p (const_tree elt1, const_tree elt2) const
84 {
85   return operand_equal_p (elt1, elt2, 0);
86 }
87 
88 /* Return true if a stepped representation is OK.  We don't allow
89    linear series for anything other than integers, to avoid problems
90    with rounding.  */
91 
92 inline bool
93 tree_vector_builder::allow_steps_p () const
94 {
95   return INTEGRAL_TYPE_P (TREE_TYPE (m_type));
96 }
97 
98 /* Return true if ELT can be interpreted as an integer.  */
99 
100 inline bool
101 tree_vector_builder::integral_p (const_tree elt) const
102 {
103   return TREE_CODE (elt) == INTEGER_CST;
104 }
105 
106 /* Return the value of element ELT2 minus the value of element ELT1.
107    Both elements are known to be INTEGER_CSTs.  */
108 
109 inline wide_int
110 tree_vector_builder::step (const_tree elt1, const_tree elt2) const
111 {
112   return wi::to_wide (elt2) - wi::to_wide (elt1);
113 }
114 
115 /* Return true if we can drop element ELT, even if the retained elements
116    are different.  Return false if this would mean losing overflow
117    information.  */
118 
119 inline bool
120 tree_vector_builder::can_elide_p (const_tree elt) const
121 {
122   return !CONSTANT_CLASS_P (elt) || !TREE_OVERFLOW (elt);
123 }
124 
125 /* Record that ELT2 is being elided, given that ELT1_PTR points to the last
126    encoded element for the containing pattern.  */
127 
128 inline void
129 tree_vector_builder::note_representative (tree *elt1_ptr, tree elt2)
130 {
131   if (CONSTANT_CLASS_P (elt2) && TREE_OVERFLOW (elt2))
132     {
133       gcc_assert (operand_equal_p (*elt1_ptr, elt2, 0));
134       if (!TREE_OVERFLOW (elt2))
135 	*elt1_ptr = elt2;
136     }
137 }
138 
139 #endif
140