https://gcc.gnu.org/g:4ca3c04a0181c37eaef23f2d50300151b428aa6f
commit 4ca3c04a0181c37eaef23f2d50300151b428aa6f
Author: Ondřej Machota <ondrejmach...@gmail.com>
Date: Fri May 9 10:54:19 2025 +0200
rtl-ssa-dce: use offset_bitmap
Diff:
---
gcc/dce.cc | 207 +++++++++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 168 insertions(+), 39 deletions(-)
diff --git a/gcc/dce.cc b/gcc/dce.cc
index 67c9ad577e67..e077485c93c3 100644
--- a/gcc/dce.cc
+++ b/gcc/dce.cc
@@ -1318,13 +1318,55 @@ public:
} // namespace
+// TODO: naalokovat prazdnou a pak resize
+// -flto_partition=none
+// -ftime_report a v build adresari zkusit insn*.cc (emit, match, recog)
+struct offset_bitmap
+{
+private:
+ int m_offset;
+ sbitmap m_bitmap;
+
+public:
+ offset_bitmap ()
+ : m_offset{0}, m_bitmap{sbitmap_alloc(0)}
+ {}
+
+ offset_bitmap (size_t size, int offset)
+ : m_offset{offset}, m_bitmap{sbitmap_alloc (size)}
+ {}
+
+ offset_bitmap (int min_index, int max_index)
+ : offset_bitmap (size_t (max_index - min_index + 1), -min_index)
+ {}
+
+ void resize(size_t size, int offset)
+ {
+ sbitmap_resize(m_bitmap, size, 0);
+ m_offset = offset;
+ }
+
+ void resize(int min_index, int max_index)
+ {
+ resize(size_t (max_index - min_index + 1), -min_index);
+ }
+
+ void clear_bit (int index) { bitmap_clear_bit (m_bitmap, index + m_offset); }
+
+ void set_bit (int index) { bitmap_set_bit (m_bitmap, index + m_offset); }
+
+ bool get_bit (int index) { return bitmap_bit_p (m_bitmap, index + m_offset);
}
+
+ ~offset_bitmap () { sbitmap_free (m_bitmap); }
+};
+
class rtl_ssa_dce
{
public:
unsigned int execute (function *);
private:
- bool is_rtx_body_prelive (const_rtx);
+ bool is_rtx_pattern_prelive (const_rtx);
bool can_delete_call (const_rtx);
bool is_rtx_prelive (const_rtx);
bool is_prelive (insn_info *);
@@ -1336,14 +1378,15 @@ private:
void reset_dead_debug ();
void sweep ();
- int offset;
-
- sbitmap mm_marked;
+ void debuggize_insn (insn_info *);
+ void debbugize_insns (const std::unordered_set<insn_info *> &);
+
+ offset_bitmap m_marked;
sbitmap mm_marked_phis;
};
bool
-rtl_ssa_dce::is_rtx_body_prelive (const_rtx insn)
+rtl_ssa_dce::is_rtx_pattern_prelive (const_rtx insn)
{
switch (GET_CODE (insn))
{
@@ -1357,9 +1400,28 @@ rtl_ssa_dce::is_rtx_body_prelive (const_rtx insn)
}
}
+// odebrat auto
+
bool
rtl_ssa_dce::can_delete_call (const_rtx insn)
{
+ gcc_checking_assert (CALL_P (insn));
+
+ // We cannot delete pure or const sibling calls because it is
+ // hard to see the result.
+ // if (!SIBLING_CALL_P (insn))
+ // // We can delete dead const or pure calls as long as they do not
+ // // infinite loop.
+ // && (RTL_CONST_OR_PURE_CALL_P (insn)
+ // && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)
+
+ // && cfun->can_delete_dead_exceptions
+ // )
+ // return true;
+ // Don't delete calls that may throw if we cannot do so.
+
+ // pridat assert na const nebo pure
+ // pouzivat gcc_checking_assert();
if (cfun->can_delete_dead_exceptions)
return true;
// if (!insn_nothrow_p (insn))
@@ -1408,8 +1470,7 @@ rtl_ssa_dce::is_rtx_prelive (const_rtx insn)
gcc_assert (GET_CODE (insn) == INSN);
// Don't delete insns that may throw if we cannot do so.
- if (!cfun->can_delete_dead_exceptions && !insn_nothrow_p (insn)
- && can_alter_cfg)
+ if (!cfun->can_delete_dead_exceptions && !insn_nothrow_p (insn))
return true;
// Callee-save restores are needed.
@@ -1417,8 +1478,8 @@ rtl_ssa_dce::is_rtx_prelive (const_rtx insn)
&& find_reg_note (insn, REG_CFA_RESTORE, NULL))
return true;
- rtx body = PATTERN (insn);
- switch (GET_CODE (body))
+ rtx pat = PATTERN (insn);
+ switch (GET_CODE (pat))
{
case CLOBBER:
case USE:
@@ -1426,13 +1487,13 @@ rtl_ssa_dce::is_rtx_prelive (const_rtx insn)
return true;
case PARALLEL:
- for (int i = XVECLEN (body, 0) - 1; i >= 0; i--)
- if (is_rtx_body_prelive (XVECEXP (body, 0, i)))
+ for (int i = XVECLEN (pat, 0) - 1; i >= 0; i--)
+ if (is_rtx_pattern_prelive (XVECEXP (pat, 0, i)))
return true;
return false;
default:
- return is_rtx_body_prelive (body);
+ return is_rtx_pattern_prelive (pat);
}
}
@@ -1472,6 +1533,7 @@ rtl_ssa_dce::is_prelive (insn_info *insn)
if (HARD_REGISTER_NUM_P (def->regno ()) && global_regs[def->regno ()])
return true;
+ // what about reload? check cse.cc
unsigned int picreg = PIC_OFFSET_TABLE_REGNUM;
if (picreg != INVALID_REGNUM && fixed_regs[picreg]
&& def->regno () == picreg)
@@ -1487,7 +1549,7 @@ rtl_ssa_dce::mark_prelive_insn (insn_info *insn,
auto_vec<set_info *> &worklist)
if (dump_file)
fprintf (dump_file, "Insn %d marked as prelive\n", insn->uid ());
- bitmap_set_bit (mm_marked, insn->uid () + offset);
+ m_marked.set_bit(insn->uid ());
// debug instruction are not added to worklist not to wake up possibly dead
// instructions
if (insn->is_debug_insn ())
@@ -1517,6 +1579,7 @@ rtl_ssa_dce::mark_prelive ()
return worklist;
}
+// kometare + PARAMETRY kapitalkami
void
rtl_ssa_dce::mark ()
{
@@ -1532,11 +1595,12 @@ rtl_ssa_dce::mark ()
continue;
// Skip already visited visited instructions.
- auto uid = insn->uid () + offset;
- if (bitmap_bit_p (mm_marked, uid) && !insn->is_phi ())
+ auto uid = insn->uid ();
+ if (m_marked.get_bit(uid) && !insn->is_phi ())
continue;
- bitmap_set_bit (mm_marked, uid);
+ m_marked.set_bit (uid);
+
use_array uses = insn->uses ();
if (insn->is_phi ())
@@ -1604,12 +1668,24 @@ rtl_ssa_dce::reset_dead_debug ()
if (parent_insn == nullptr)
continue;
// If we depend on a dead instruction, clear current instruction uses.
- sbitmap marked = parent_insn->is_phi () ? mm_marked_phis : mm_marked;
- int uid = parent_insn->is_phi () ? static_cast<phi_info *> (def)->uid () :
parent_insn->uid () + offset;
- if (!bitmap_bit_p (marked, uid)) {
+ bool shouldReset = false;
+ if (parent_insn->is_phi ()) {
+ shouldReset = bitmap_bit_p(mm_marked_phis, static_cast<phi_info *>
(def)->uid ());
+ } else {
+ shouldReset = m_marked.get_bit(parent_insn->uid ());
+ }
+
+ if (shouldReset) {
reset_dead_debug_insn (insn);
break;
}
+
+ // sbitmap marked = parent_insn->is_phi () ? mm_marked_phis : mm_marked;
+ // int uid = parent_insn->is_phi () ? static_cast<phi_info *> (def)->uid
() : parent_insn->uid () + offset;
+ // if (!bitmap_bit_p (marked, uid)) {
+ // reset_dead_debug_insn (insn);
+ // break;
+ // }
}
}
}
@@ -1625,7 +1701,7 @@ rtl_ssa_dce::sweep ()
for (insn_info *insn : crtl->ssa->nondebug_insns ())
{
// Artificial or marked insns should not be deleted.
- if (insn->is_artificial () || bitmap_bit_p (mm_marked, insn->uid () +
offset))
+ if (insn->is_artificial () || m_marked.get_bit (insn->uid ()))
continue;
if (dump_file)
@@ -1668,11 +1744,10 @@ rtl_ssa_dce::execute (function *fn)
count++;
}
- offset = -artificial_min;
+ m_marked.resize(artificial_min, real_max);
// std::cout << "real_max: " << real_max << '\n';
// std::cout << "artificial_min: " << artificial_min << '\n';
// std::cout << "total: " << real_max - artificial_min + 3 << '\n';
- // std::cout << "Offset: " << offset << '\n';
// std::cout << "count: " << count << '\n';
unsigned int phi_node_max = 0;
@@ -1681,8 +1756,6 @@ rtl_ssa_dce::execute (function *fn)
phi_node_max = std::max (phi_node_max, phi->uid ());
// std::cout << "phi_node_max: " << phi_node_max << '\n';
- mm_marked = sbitmap_alloc(real_max - artificial_min + 3);
- bitmap_clear(mm_marked);
mm_marked_phis = sbitmap_alloc(phi_node_max + 1);
bitmap_clear(mm_marked_phis);
@@ -1715,7 +1788,6 @@ rtl_ssa_dce::execute (function *fn)
if (crtl->ssa->perform_pending_updates ())
cleanup_cfg (0);
- sbitmap_free(mm_marked);
sbitmap_free(mm_marked_phis);
delete crtl->ssa;
crtl->ssa = nullptr;
@@ -1754,7 +1826,8 @@ rtl_ssa_dce::propagate_dead_phis ()
if (dump_file)
fprintf (dump_file, "Debug insns %d depends on dead phi.\n",
insn->uid ());
- bitmap_clear_bit (mm_marked, insn->uid ());
+
+ m_marked.clear_bit (insn->uid ());
// debug instructions dont have chains
continue;
}
@@ -1762,12 +1835,12 @@ rtl_ssa_dce::propagate_dead_phis ()
// mark
if (insn->is_phi ())
{
- gcc_assert (!bitmap_bit_p(mm_marked_phis, static_cast<phi_info *>
(set)->uid ()));
+ gcc_checking_assert (!bitmap_bit_p(mm_marked_phis,
static_cast<phi_info *> (set)->uid ()));
visited_dead_phis.emplace (static_cast<phi_info *> (set));
}
else
{
- gcc_assert (!bitmap_bit_p (mm_marked, insn->uid () + offset));
+ gcc_checking_assert (!m_marked.get_bit (insn->uid ()));
depends_on_dead_phi.emplace (insn);
}
@@ -1797,20 +1870,72 @@ rtl_ssa_dce::propagate_dead_phis ()
return depends_on_dead_phi;
}
-static void
-rtl_ssa_dce_debuggize (insn_info *insn)
+void
+rtl_ssa_dce::debuggize_insn (insn_info *insn)
{
- if (insn->is_phi ())
- {
- return;
- }
+
+}
- if (insn->is_debug_insn ())
- {
- // we need to fix dependencies of this instruction because they might
have
- // changed
- return;
+void
+rtl_ssa_dce::debbugize_insns (const std::unordered_set<insn_info *>
&depends_on_dead_phi)
+{
+ for (insn_info *insn : crtl->ssa->reverse_all_insns ()) {
+ if (insn->is_artificial () ||
+ (m_marked.get_bit (insn->uid ()) && !insn->is_debug_insn()))
+ continue;
+
+ // TODO: reset dead debug instructions - those that are dependend on a
dead phi
+ if (depends_on_dead_phi.count (insn) > 0) {
+ if (insn->is_debug_insn ())
+ reset_dead_debug_insn (insn);
+ continue;
}
+
+ gcc_checking_assert(insn->is_real ());
+
+ rtx_insn *rtl = insn->rtl ();
+ def_array defs = insn->defs ();
+ // def_info* s = nullptr;
+ // s->kind() == access_kind::SET
+ rtx set;
+ // debbugize_insns should be called only if MAY_HAVE_DEBUG_BIND_INSNS
+ if (MAY_HAVE_DEBUG_BIND_INSNS
+ && (set = single_set (rtl)) != NULL_RTX
+ && !(*defs.begin ())->has_nondebug_insn_uses()
+ // && is_dead_reg (SET_DEST (set), counts)
+ // Proc tam byla tato podminka?
+ // - debug statementy se sypou za kazdou definici ve zdrojaku, tedy
+ // proto se chci ptat na to, kdyz existuje debug pouziti, tak je to
+ // zajimava promenna
+ /* Used at least once in some DEBUG_INSN. */
+ // && counts[REGNO (SET_DEST (set)) + nreg] > 0
+ // Tohle je ten bind nebo cast debug instrukce?
+ /* And set exactly once. */
+ // && counts[REGNO (SET_DEST (set)) + nreg * 2] == 1
+ && !side_effects_p (SET_SRC (set))
+ && asm_noperands (PATTERN (rtl)) < 0)
+ {
+ // TODO: musime predratovat zavisle debug insn - vsechny uses na nove
+ // vytvorenou debug insn
+ /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
+ rtx dval = make_debug_expr_from_rtl (SET_DEST (set));
+
+ /* Emit a debug bind insn before the insn in which
+ reg dies. */
+ rtx bind_var_loc =
+ gen_rtx_VAR_LOCATION (GET_MODE (SET_DEST (set)),
+ DEBUG_EXPR_TREE_DECL (dval),
+ SET_SRC (set),
+ VAR_INIT_STATUS_INITIALIZED);
+ // count_reg_usage (bind_var_loc, counts + nreg, NULL_RTX, 1);
+
+ rtx_insn *bind = emit_debug_insn_before (bind_var_loc, rtl);
+
+ // if (replacements == NULL)
+ // replacements = XCNEWVEC (rtx, nreg);
+ // replacements[REGNO (SET_DEST (set))] = dval;
+ }
+ }
}
static void
@@ -1828,6 +1953,10 @@ test (insn_info *insn)
DEBUG_EXPR_TREE_DECL (dval), SET_SRC (set),
VAR_INIT_STATUS_INITIALIZED);
+ obstack_watermark watermark = crtl->ssa->new_change_attempt();
+ // Radeji bych zde videl pridani dval do rtl ssa
+ // crtl->ssa->create_insn(watermark, DEBUG_INSN, rtx pat);
+
// TODO : change ssa form - we have to keep uses in the first debug insn and
// delete other instructions
// make dval available in the following iteration
