diff options
Diffstat (limited to 'gcc/tree.h')
| -rw-r--r-- | gcc/tree.h | 129 |
1 files changed, 94 insertions, 35 deletions
@@ -5120,20 +5120,6 @@ extern bool anon_aggrname_p (const_tree); /* The tree and const_tree overload templates. */ namespace wi { - template <> - struct int_traits <const_tree> - { - static const enum precision_type precision_type = VAR_PRECISION; - static const bool host_dependent_precision = false; - static const bool is_sign_extended = false; - static unsigned int get_precision (const_tree); - static wi::storage_ref decompose (HOST_WIDE_INT *, unsigned int, - const_tree); - }; - - template <> - struct int_traits <tree> : public int_traits <const_tree> {}; - template <int N> class extended_tree { @@ -5157,42 +5143,115 @@ namespace wi static const unsigned int precision = N; }; - generic_wide_int <extended_tree <WIDE_INT_MAX_PRECISION> > - to_widest (const_tree); - - generic_wide_int <extended_tree <ADDR_MAX_PRECISION> > to_offset (const_tree); + typedef const generic_wide_int <extended_tree <WIDE_INT_MAX_PRECISION> > + tree_to_widest_ref; + typedef const generic_wide_int <extended_tree <ADDR_MAX_PRECISION> > + tree_to_offset_ref; + typedef const generic_wide_int<wide_int_ref_storage<false, false> > + tree_to_wide_ref; + tree_to_widest_ref to_widest (const_tree); + tree_to_offset_ref to_offset (const_tree); + tree_to_wide_ref to_wide (const_tree); wide_int to_wide (const_tree, unsigned int); } -inline unsigned int -wi::int_traits <const_tree>::get_precision (const_tree tcst) -{ - return TYPE_PRECISION (TREE_TYPE (tcst)); -} +/* Refer to INTEGER_CST T as though it were a widest_int. -/* Convert the tree_cst X into a wide_int of PRECISION. */ -inline wi::storage_ref -wi::int_traits <const_tree>::decompose (HOST_WIDE_INT *, - unsigned int precision, const_tree x) -{ - gcc_checking_assert (precision == TYPE_PRECISION (TREE_TYPE (x))); - return wi::storage_ref (&TREE_INT_CST_ELT (x, 0), TREE_INT_CST_NUNITS (x), - precision); -} + This function gives T's actual numerical value, influenced by the + signedness of its type. For example, a signed byte with just the + top bit set would be -128 while an unsigned byte with the same + bit pattern would be 128. + + This is the right choice when operating on groups of INTEGER_CSTs + that might have different signedness or precision. It is also the + right choice in code that specifically needs an approximation of + infinite-precision arithmetic instead of normal modulo arithmetic. + + The approximation of infinite precision is good enough for realistic + numbers of additions and subtractions of INTEGER_CSTs (where + "realistic" includes any number less than 1 << 31) but it cannot + represent the result of multiplying the two largest supported + INTEGER_CSTs. The overflow-checking form of wi::mul provides a way + of multiplying two arbitrary INTEGER_CSTs and checking that the + result is representable as a widest_int. + + Note that any overflow checking done on these values is relative to + the range of widest_int rather than the range of a TREE_TYPE. + + Calling this function should have no overhead in release builds, + so it is OK to call it several times for the same tree. If it is + useful for readability reasons to reduce the number of calls, + it is more efficient to use: + + wi::tree_to_widest_ref wt = wi::to_widest (t); + + instead of: -inline generic_wide_int <wi::extended_tree <WIDE_INT_MAX_PRECISION> > + widest_int wt = wi::to_widest (t). */ + +inline wi::tree_to_widest_ref wi::to_widest (const_tree t) { return t; } -inline generic_wide_int <wi::extended_tree <ADDR_MAX_PRECISION> > +/* Refer to INTEGER_CST T as though it were an offset_int. + + This function is an optimisation of wi::to_widest for cases + in which T is known to be a bit or byte count in the range + (-(2 ^ (N + BITS_PER_UNIT)), 2 ^ (N + BITS_PER_UNIT)), where N is + the target's address size in bits. + + This is the right choice when operating on bit or byte counts as + untyped numbers rather than M-bit values. The wi::to_widest comments + about addition, subtraction and multiplication apply here: sequences + of 1 << 31 additions and subtractions do not induce overflow, but + multiplying the largest sizes might. Again, + + wi::tree_to_offset_ref wt = wi::to_offset (t); + + is more efficient than: + + offset_int wt = wi::to_offset (t). */ + +inline wi::tree_to_offset_ref wi::to_offset (const_tree t) { return t; } +/* Refer to INTEGER_CST T as though it were a wide_int. + + In contrast to the approximation of infinite-precision numbers given + by wi::to_widest and wi::to_offset, this function treats T as a + signless collection of N bits, where N is the precision of T's type. + As with machine registers, signedness is determined by the operation + rather than the operands; for example, there is a distinction between + signed and unsigned division. + + This is the right choice when operating on values with the same type + using normal modulo arithmetic. The overflow-checking forms of things + like wi::add check whether the result can be represented in T's type. + + Calling this function should have no overhead in release builds, + so it is OK to call it several times for the same tree. If it is + useful for readability reasons to reduce the number of calls, + it is more efficient to use: + + wi::tree_to_wide_ref wt = wi::to_wide (t); + + instead of: + + wide_int wt = wi::to_wide (t). */ + +inline wi::tree_to_wide_ref +wi::to_wide (const_tree t) +{ + return wi::storage_ref (&TREE_INT_CST_ELT (t, 0), TREE_INT_CST_NUNITS (t), + TYPE_PRECISION (TREE_TYPE (t))); +} + /* Convert INTEGER_CST T to a wide_int of precision PREC, extending or truncating as necessary. When extending, use sign extension if T's type is signed and zero extension if T's type is unsigned. */ @@ -5200,7 +5259,7 @@ wi::to_offset (const_tree t) inline wide_int wi::to_wide (const_tree t, unsigned int prec) { - return wide_int::from (t, prec, TYPE_SIGN (TREE_TYPE (t))); + return wide_int::from (wi::to_wide (t), prec, TYPE_SIGN (TREE_TYPE (t))); } template <int N> |