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Add "fast" conversions from arrays to bitmaps

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This patch adds a bitmap_view<X> class that creates a read-only,
on-stack bitmap representation of an array-like object X.  The main
use case is to allow HARD_REG_SETs to be used in REG_SET (i.e. bitmap)
operations.

For now it only handles constant-sized arrays, but I've tried to
define the types in a way that could handle variable-sized arrays
in future (although less efficiently).  E.g. this might be useful
for combining bitmaps and sbitmaps.

For the read-only view to work as intended, I needed to make
bitmap_bit_p take a const_bitmap instead of a bitmap.  Logically
the bitmap really is read-only, but we update the "current" and
"indx" fields of the bitmap_head after doing a search.

2019-09-09  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* array-traits.h: New file.
	* coretypes.h (array_traits, bitmap_view): New types.
	* bitmap.h: Include "array-traits.h"
	(bitmap_bit_p): Take a const_bitmap instead of a bitmap.
	(base_bitmap_view, bitmap_view): New classes.
	* bitmap.c (bitmap_bit_p): Take a const_bitmap instead of a bitmap.
	* hard-reg-set.h: Include array-traits.h.
	(array_traits<HARD_REG_SET>): New struct.
	* regset.h (IOR_REG_SET_HRS): New macro.
	* loop-iv.c (simplify_using_initial_values): Use IOR_REG_SET_HRS
	rather than iterating over each hard register.
	* sched-deps.c (sched_analyze_insn): Likewise.
	* sel-sched-ir.c (setup_id_implicit_regs): Likewise.

From-SVN: r275536
This commit is contained in:
Richard Sandiford 2019-09-09 18:01:47 +00:00 • committed by Richard Sandiford
parent 75f4e3a1b3
commit 148909bc70
10 changed files with 219 additions and 21 deletions
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16
gcc/ChangeLog
View file

@ -1,3 +1,19 @@
2019-09-09 Richard Sandiford <richard.sandiford@arm.com>
* array-traits.h: New file.
* coretypes.h (array_traits, bitmap_view): New types.
* bitmap.h: Include "array-traits.h"
(bitmap_bit_p): Take a const_bitmap instead of a bitmap.
(base_bitmap_view, bitmap_view): New classes.
* bitmap.c (bitmap_bit_p): Take a const_bitmap instead of a bitmap.
* hard-reg-set.h: Include array-traits.h.
(array_traits<HARD_REG_SET>): New struct.
* regset.h (IOR_REG_SET_HRS): New macro.
* loop-iv.c (simplify_using_initial_values): Use IOR_REG_SET_HRS
rather than iterating over each hard register.
* sched-deps.c (sched_analyze_insn): Likewise.
* sel-sched-ir.c (setup_id_implicit_regs): Likewise.
2019-09-09 Richard Sandiford <richard.sandiford@arm.com>
* ira-int.h (ior_hard_reg_conflicts): Take a const_hard_reg_set

48
gcc/array-traits.h Normal file
View file

@ -0,0 +1,48 @@
/* Descriptions of array-like objects.
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#ifndef GCC_ARRAY_TRAITS_H
#define GCC_ARRAY_TRAITS_H
/* Implementation for single integers (and similar types). */
template<typename T, T zero = T (0)>
struct scalar_array_traits
{
typedef T element_type;
static const bool has_constant_size = true;
static const size_t constant_size = 1;
static const T *base (const T &x) { return &x; }
static size_t size (const T &) { return 1; }
};
template<typename T>
struct array_traits : scalar_array_traits<T> {};
/* Implementation for arrays with a static size. */
template<typename T, size_t N>
struct array_traits<T[N]>
{
typedef T element_type;
static const bool has_constant_size = true;
static const size_t constant_size = N;
static const T *base (const T (&x)[N]) { return x; }
static size_t size (const T (&x)[N]) { return N; }
};
#endif

8
gcc/bitmap.c
View file

@ -979,17 +979,17 @@ bitmap_set_bit (bitmap head, int bit)
/* Return whether a bit is set within a bitmap. */
int
bitmap_bit_p (bitmap head, int bit)
bitmap_bit_p (const_bitmap head, int bit)
{
unsigned int indx = bit / BITMAP_ELEMENT_ALL_BITS;
bitmap_element *ptr;
const bitmap_element *ptr;
unsigned bit_num;
unsigned word_num;
if (!head->tree_form)
ptr = bitmap_list_find_element (head, indx);
ptr = bitmap_list_find_element (const_cast<bitmap> (head), indx);
else
ptr = bitmap_tree_find_element (head, indx);
ptr = bitmap_tree_find_element (const_cast<bitmap> (head), indx);
if (ptr == 0)
return 0;

122
gcc/bitmap.h
View file

@ -210,6 +210,7 @@ along with GCC; see the file COPYING3. If not see
on which many random-access membership tests will happen. */
#include "obstack.h"
#include "array-traits.h"
/* Bitmap memory usage. */
class bitmap_usage: public mem_usage
@ -435,7 +436,7 @@ extern bool bitmap_clear_bit (bitmap, int);
extern bool bitmap_set_bit (bitmap, int);
/* Return true if a bit is set in a bitmap. */
extern int bitmap_bit_p (bitmap, int);
extern int bitmap_bit_p (const_bitmap, int);
/* Debug functions to print a bitmap. */
extern void debug_bitmap (const_bitmap);
@ -956,4 +957,123 @@ class auto_bitmap
bitmap_head m_bits;
};
/* Base class for bitmap_view; see there for details. */
template<typename T, typename Traits = array_traits<T> >
class base_bitmap_view
{
public:
typedef typename Traits::element_type array_element_type;
base_bitmap_view (const T &, bitmap_element *);
operator const_bitmap () const { return &m_head; }
private:
base_bitmap_view (const base_bitmap_view &);
bitmap_head m_head;
};
/* Provides a read-only bitmap view of a single integer bitmask or a
constant-sized array of integer bitmasks, or of a wrapper around such
bitmasks. */
template<typename T, typename Traits>
class bitmap_view<T, Traits, true> : public base_bitmap_view<T, Traits>
{
public:
bitmap_view (const T &array)
: base_bitmap_view<T, Traits> (array, m_bitmap_elements) {}
private:
/* How many bitmap_elements we need to hold a full T. */
static const size_t num_bitmap_elements
= CEIL (CHAR_BIT
* sizeof (typename Traits::element_type)
* Traits::constant_size,
BITMAP_ELEMENT_ALL_BITS);
bitmap_element m_bitmap_elements[num_bitmap_elements];
};
/* Initialize the view for array ARRAY, using the array of bitmap
elements in BITMAP_ELEMENTS (which is known to contain enough
entries). */
template<typename T, typename Traits>
base_bitmap_view<T, Traits>::base_bitmap_view (const T &array,
bitmap_element *bitmap_elements)
{
m_head.obstack = NULL;
/* The code currently assumes that each element of ARRAY corresponds
to exactly one bitmap_element. */
const size_t array_element_bits = CHAR_BIT * sizeof (array_element_type);
STATIC_ASSERT (BITMAP_ELEMENT_ALL_BITS % array_element_bits == 0);
size_t array_step = BITMAP_ELEMENT_ALL_BITS / array_element_bits;
size_t array_size = Traits::size (array);
/* Process each potential bitmap_element in turn. The loop is written
this way rather than per array element because usually there are
only a small number of array elements per bitmap element (typically
two or four). The inner loops should therefore unroll completely. */
const array_element_type *array_elements = Traits::base (array);
unsigned int indx = 0;
for (size_t array_base = 0;
array_base < array_size;
array_base += array_step, indx += 1)
{
/* How many array elements are in this particular bitmap_element. */
unsigned int array_count
= (STATIC_CONSTANT_P (array_size % array_step == 0)
? array_step : MIN (array_step, array_size - array_base));
/* See whether we need this bitmap element. */
array_element_type ior = array_elements[array_base];
for (size_t i = 1; i < array_count; ++i)
ior |= array_elements[array_base + i];
if (ior == 0)
continue;
/* Grab the next bitmap element and chain it. */
bitmap_element *bitmap_element = bitmap_elements++;
if (m_head.current)
m_head.current->next = bitmap_element;
else
m_head.first = bitmap_element;
bitmap_element->prev = m_head.current;
bitmap_element->next = NULL;
bitmap_element->indx = indx;
m_head.current = bitmap_element;
m_head.indx = indx;
/* Fill in the bits of the bitmap element. */
if (array_element_bits < BITMAP_WORD_BITS)
{
/* Multiple array elements fit in one element of
bitmap_element->bits. */
size_t array_i = array_base;
for (unsigned int word_i = 0; word_i < BITMAP_ELEMENT_WORDS;
++word_i)
{
BITMAP_WORD word = 0;
for (unsigned int shift = 0;
shift < BITMAP_WORD_BITS && array_i < array_size;
shift += array_element_bits)
word |= array_elements[array_i++] << shift;
bitmap_element->bits[word_i] = word;
}
}
else
{
/* Array elements are the same size as elements of
bitmap_element->bits, or are an exact multiple of that size. */
unsigned int word_i = 0;
for (unsigned int i = 0; i < array_count; ++i)
for (unsigned int shift = 0; shift < array_element_bits;
shift += BITMAP_WORD_BITS)
bitmap_element->bits[word_i++]
= array_elements[array_base + i] >> shift;
while (word_i < BITMAP_ELEMENT_WORDS)
bitmap_element->bits[word_i++] = 0;
}
}
}
#endif /* GCC_BITMAP_H */

8
gcc/coretypes.h
View file

@ -153,6 +153,14 @@ struct cl_option_handlers;
struct diagnostic_context;
class pretty_printer;
template<typename T> struct array_traits;
/* Provides a read-only bitmap view of a single integer bitmask or an
array of integer bitmasks, or of a wrapper around such bitmasks. */
template<typename T, typename Traits = array_traits<T>,
bool has_constant_size = Traits::has_constant_size>
class bitmap_view;
/* Address space number for named address space support. */
typedef unsigned char addr_space_t;

12
gcc/hard-reg-set.h
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@ -20,6 +20,8 @@ along with GCC; see the file COPYING3. If not see
#ifndef GCC_HARD_REG_SET_H
#define GCC_HARD_REG_SET_H
#include "array-traits.h"
/* Define the type of a set of hard registers. */
/* HARD_REG_ELT_TYPE is a typedef of the unsigned integral type which
@ -115,6 +117,16 @@ struct HARD_REG_SET
};
typedef const HARD_REG_SET &const_hard_reg_set;
template<>
struct array_traits<HARD_REG_SET>
{
typedef HARD_REG_ELT_TYPE element_type;
static const bool has_constant_size = true;
static const size_t constant_size = HARD_REG_SET_LONGS;
static const element_type *base (const HARD_REG_SET &x) { return x.elts; }
static size_t size (const HARD_REG_SET &) { return HARD_REG_SET_LONGS; }
};
#endif
/* HARD_REG_SET wrapped into a structure, to make it possible to

10
gcc/loop-iv.c
View file

@ -1972,14 +1972,8 @@ simplify_using_initial_values (class loop *loop, enum rtx_code op, rtx *expr)
CLEAR_REG_SET (this_altered);
note_stores (insn, mark_altered, this_altered);
if (CALL_P (insn))
{
/* Kill all call clobbered registers. */
unsigned int i;
hard_reg_set_iterator hrsi;
EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call,
0, i, hrsi)
SET_REGNO_REG_SET (this_altered, i);
}
/* Kill all call clobbered registers. */
IOR_REG_SET_HRS (this_altered, regs_invalidated_by_call);
if (suitable_set_for_replacement (insn, &dest, &src))
{

4
gcc/regset.h
View file

@ -64,6 +64,10 @@ typedef bitmap regset;
/* Inclusive or a register set with a second register set. */
#define IOR_REG_SET(TO, FROM) bitmap_ior_into (TO, FROM)
/* Same, but with FROM being a HARD_REG_SET. */
#define IOR_REG_SET_HRS(TO, FROM) \
bitmap_ior_into (TO, bitmap_view<HARD_REG_SET> (FROM))
/* Exclusive or a register set with a second register set. */
#define XOR_REG_SET(TO, FROM) bitmap_xor_into (TO, FROM)

7
gcc/sched-deps.c
View file

@ -3332,10 +3332,9 @@ sched_analyze_insn (class deps_desc *deps, rtx x, rtx_insn *insn)
IOR_REG_SET (&deps->reg_last_in_use, reg_pending_uses);
IOR_REG_SET (&deps->reg_last_in_use, reg_pending_clobbers);
IOR_REG_SET (&deps->reg_last_in_use, reg_pending_sets);
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (TEST_HARD_REG_BIT (implicit_reg_pending_uses, i)
|| TEST_HARD_REG_BIT (implicit_reg_pending_clobbers, i))
SET_REGNO_REG_SET (&deps->reg_last_in_use, i);
IOR_REG_SET_HRS (&deps->reg_last_in_use,
implicit_reg_pending_uses
| implicit_reg_pending_clobbers);
/* Set up the pending barrier found. */
deps->last_reg_pending_barrier = reg_pending_barrier;

5
gcc/sel-sched-ir.c
View file

@ -2661,12 +2661,9 @@ setup_id_implicit_regs (idata_t id, insn_t insn)
return;
HARD_REG_SET temp;
unsigned regno;
hard_reg_set_iterator hrsi;
get_implicit_reg_pending_clobbers (&temp, insn);
EXECUTE_IF_SET_IN_HARD_REG_SET (temp, 0, regno, hrsi)
SET_REGNO_REG_SET (IDATA_REG_SETS (id), regno);
IOR_REG_SET_HRS (IDATA_REG_SETS (id), temp);
}
/* Setup register sets describing INSN in ID. */