https://gcc.gnu.org/g:7cbb0ce1fbec2adad90bd7c14342243ea9505ff9
commit 7cbb0ce1fbec2adad90bd7c14342243ea9505ff9
Author: Ondřej Machota <ondrejmach...@gmail.com>
Date: Mon Mar 31 11:19:18 2025 +0200
rtl-ssa-dce: format code
Diff:
---
gcc/dce.cc | 306 +++++++++++++++++++------------------------------------------
1 file changed, 94 insertions(+), 212 deletions(-)
diff --git a/gcc/dce.cc b/gcc/dce.cc
index a90a8d9ccf53..d16cec35eb16 100644
--- a/gcc/dce.cc
+++ b/gcc/dce.cc
@@ -1325,8 +1325,10 @@ struct offset_bitmap {
sbitmap m_bitmap;
public:
- 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), min_index) {}
+ 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), min_index) {}
void clear_bit(int index) {
bitmap_clear_bit(m_bitmap, index + m_offset);
@@ -1345,75 +1347,7 @@ struct offset_bitmap {
}
};
-bool side_effects_with_mem (const_rtx x)
-{
- const RTX_CODE code = GET_CODE (x);
- switch (code)
- {
- case LABEL_REF:
- case SYMBOL_REF:
- case CONST:
- CASE_CONST_ANY:
- case PC:
- case REG:
- case SCRATCH:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- case VAR_LOCATION:
- return false;
-
- case CLOBBER:
- /* Reject CLOBBER with a non-VOID mode. These are made by combine.cc
- when some combination can't be done. If we see one, don't think
- that we can simplify the expression. */
- return (GET_MODE (x) != VOIDmode);
-
- case PRE_INC:
- case PRE_DEC:
- case POST_INC:
- case POST_DEC:
- case PRE_MODIFY:
- case POST_MODIFY:
- case CALL:
- case UNSPEC_VOLATILE:
- return true;
-
- case MEM: // We might want tu return true iff volatile or mem is a
destination
- // write or possible null read
- case ASM_INPUT:
- case ASM_OPERANDS:
- return true;
-
- default:
- break;
- }
-
- /* Recursively scan the operands of this expression. */
-
- {
- const char *fmt = GET_RTX_FORMAT (code);
- int i;
-
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- if (side_effects_with_mem (XEXP (x, i)))
- return true;
- }
- else if (fmt[i] == 'E')
- {
- int j;
- for (j = 0; j < XVECLEN (x, i); j++)
- if (side_effects_with_mem (XVECEXP (x, i, j)))
- return true;
- }
- }
- }
- return false;
-}
-
-bool is_ssa_prelive(const_rtx insn) {
+bool is_rtx_prelive(const_rtx insn) {
switch (GET_CODE(insn)) {
case PREFETCH:
case UNSPEC:
@@ -1429,15 +1363,12 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
gcc_assert(insn != nullptr);
if (!NONJUMP_INSN_P (insn))
- {
- // This handles jumps, debug_insns, call_insn, ...
+ /* This handles jumps, debug_insns, call_insn, ... */
return true;
- }
- // TODO : handle calls correctly
if (CALL_P (insn)
/* We cannot delete pure or const sibling calls because it is
- hard to see the result. */
+ hard to see the result. */
&& (!SIBLING_CALL_P (insn))
/* We can delete dead const or pure calls as long as they do not
infinite loop. */
@@ -1447,111 +1378,74 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
return true;
// return !find_call_stack_args (as_a <rtx_call_insn *> (insn), false,
fast, arg_stores);
- // Only rtx_insn should be handled here
+ /* Only rtx_insn should be handled here */
gcc_assert(GET_CODE(insn) == INSN);
/* Don't delete insns that may throw if we cannot do so. */
- if (!(cfun->can_delete_dead_exceptions && can_alter_cfg) && !insn_nothrow_p
(insn))
+ if (!(cfun->can_delete_dead_exceptions && can_alter_cfg)
+ && !insn_nothrow_p (insn))
return true;
/* Callee-save restores are needed. */
- if (RTX_FRAME_RELATED_P (insn) && crtl->shrink_wrapped_separate &&
find_reg_note (insn, REG_CFA_RESTORE, NULL))
+ if (RTX_FRAME_RELATED_P (insn) && crtl->shrink_wrapped_separate
+ && find_reg_note (insn, REG_CFA_RESTORE, NULL))
return true;
- // TODO : asm_noperands???
-
rtx body = PATTERN(insn);
switch (GET_CODE(body)) {
case CLOBBER: // gcc/gcc/testsuite/gcc.c-torture/compile/20000605-1.c
case USE:
case VAR_LOCATION:
- case PREFETCH: // This and following case might be removed since they are
part of deletable_insn_p_1
- case TRAP_IF:
+ /* Following cases might be removed since they are part of is_rtx_prelive
*/
+ case PREFETCH:
+ case TRAP_IF: /* testsuite/gcc.c-torture/execute/20020418-1.c */
case UNSPEC:
return true;
case PARALLEL:
for (int i = XVECLEN (body, 0) - 1; i >= 0; i--)
- if (is_ssa_prelive (XVECEXP (body, 0, i)))
+ if (is_rtx_prelive (XVECEXP (body, 0, i)))
return true;
return false;
default:
- return is_ssa_prelive (body);
+ return is_rtx_prelive (body);
}
-
- // See deletable_insn_p_1 for UNSPEC. TRAP_IF is caught by
may_trap_or_fault_p
-
- // may_trap_or_fault_p helps a lot to pass some tests from
RUNTESTSFLAGS=execute.exp
- // e. g. this one: testsuite/gcc.c-torture/execute/20020418-1.c
- // TODO : debug the testcase
- // It seems that the issue was due to trap_if rtl insn and fixed with
may_trap_or_fault_p
- if (side_effects_with_mem(body)) // may_trap_or_fault_p(body) replaced by
TRAP_IF
- return true;
-
- return false;
}
bool is_prelive(insn_info *insn)
{
- if (insn->is_artificial()) // phis are never prelive, bb head + end are
artificial
+ /* Phi insns are never prelive, bb head + end also are artificial */
+ if (insn->is_artificial())
return false;
- /*
- * There are a few functions we can use to detect if an instruction is
- * inherently live:
- * rtlanal.cc:
- * bool side_effects_p (const_rtx x);
- * bool volatile_insn_p (const_rtx x);
- *
- * rtlanal.h
- * bool has_side_effects (); inside class rtx_properties
- *
- * dce.cc:
- * static bool deletable_insn_p_1(rtx body); uses bool volatile_insn_p
(const_rtx x);
- * static bool deletable_insn_p(rtx_insn *insn, bool fast, bitmap
arg_stores);
- *
- * Possibly the most accurate way would be to rewrite `static bool
- * deletable_insn_p(rtx_insn *insn, bool fast, bitmap arg_stores);`
- *
- */
-
- // Now, we only have to handle rtx insns
gcc_assert (insn->is_real());
auto rtl = insn->rtl();
for (def_info * def : insn->defs()) {
- // The purpose of this pass is not to eliminate stores to memory...
- if (def->is_mem()) { // TODO : clobbered memory?
+ /* The purpose of this pass is not to eliminate stores to memory... */
+ if (def->is_mem())
+ // TODO : clobbered memory?
return true;
- }
gcc_assert(def->is_reg());
- // this ignores clobbers, which is probably fine
-
-
- // TODO : find something similar to mark_artificial_uses to mark only
- // artificially-used registers
- // check: df_get_regular_block_artificial_uses
- // That should fix following test as assume
- // gcc.c-torture/execute/20000503-1.c - flags register is unused
+ /* this ignores clobbers, which is probably fine */
+
+ /* TODO : find something similar to mark_artificial_uses to mark only
+ artificially-used registers.
+ - df_get_regular_block_artificial_uses
+ That should fix following test as assume
+ gcc.c-torture/execute/20000503-1.c - flags register is unused. Not all
+ hard registers should be marked... */
if (def->kind() != access_kind::SET)
continue;
- // We need to perform some kind of reset_unmarked_insns_debug_uses
- // to be able to reproduce ud_dce - now only 4 tests are falling
- // because of debug_insn being dependent on parallel with set flags
- // gcc.c-torture/execute/20051215-1.c
- // gcc.c-torture/execute/20100805-1.c
- // gcc.c-torture/execute/pr39339.c
- // gcc.c-torture/execute/pr47925.c
-
- // This might be messed up a bit
+ /* This might be messed up a bit */
if (def->regno() == FRAME_POINTER_REGNUM
|| def->regno() == STACK_POINTER_REGNUM)
return true;
- // needed by gcc.c-torture/execute/pr51447.c
+ /* needed by gcc.c-torture/execute/pr51447.c */
if (HARD_REGISTER_NUM_P (def->regno())
&& global_regs[def->regno()])
return true;
@@ -1573,26 +1467,27 @@ bool is_prelive(insn_info *insn)
// TODO : eh?
- // if (def->kind() == access_kind::SET
- // && (HARD_REGISTER_NUM_P(def->regno())
- // || (pic_offset_table_rtx != nullptr
- // && def->regno() == REGNO (pic_offset_table_rtx)
- // && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER))
- // ) {
- // // find_reg_note(insn->rtl(), REG_UNUSED, def->regno())
- // return true;
- // }
+ /*
+ if (def->kind() == access_kind::SET
+ && (HARD_REGISTER_NUM_P(def->regno())
+ || (pic_offset_table_rtx != nullptr
+ && def->regno() == REGNO (pic_offset_table_rtx)
+ && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER))
+ ) {
+ // find_reg_note(insn->rtl(), REG_UNUSED, def->regno())
+ return true;
+ } */
}
return is_rtx_insn_prelive(rtl);
}
static void
-rtl_ssa_dce_mark_live(insn_info *info, vec<insn_info *> &worklist,
std::unordered_set<insn_info *> &marked)
+rtl_ssa_dce_mark_prelive(insn_info *info, vec<insn_info *> &worklist,
+ std::unordered_set<insn_info *> &marked)
{
- int info_uid = info->uid();
if (dump_file)
- fprintf(dump_file, " Adding insn %d to worklist\n", info_uid);
+ fprintf(dump_file, "Insn %d is prelive\n", info->uid());
marked.emplace(info);
worklist.safe_push(info);
@@ -1601,17 +1496,10 @@ rtl_ssa_dce_mark_live(insn_info *info, vec<insn_info *>
&worklist, std::unordere
static auto_vec<insn_info *>
rtl_ssa_dce_prelive(std::unordered_set<insn_info *> &marked)
{
- insn_info *next;
auto_vec<insn_info *> worklist;
- for (insn_info *insn = crtl->ssa->first_insn(); insn; insn = next)
- {
- next = insn->next_any_insn();
+ for (insn_info * insn : crtl->ssa->all_insns()) {
if (is_prelive(insn))
- {
- rtl_ssa_dce_mark_live(insn, worklist, marked);
- }
-
- // Might help to fix -DPREVENT_OPTIMIZATION? (insn->can_be_optimized () ||
insn->is_debug_insn ())
+ rtl_ssa_dce_mark_prelive(insn, worklist, marked);
}
return worklist;
@@ -1621,85 +1509,77 @@ static std::unordered_set<insn_info *>
rtl_ssa_dce_mark()
{
std::unordered_set<insn_info *> marked{};
- // phi insn might have more that one phi node:
gcc/gcc/testsuite/gcc.c-torture/execute/20000224-1.c
+ /* Phi insn might have more that one phi node:
gcc/gcc/testsuite/gcc.c-torture/execute/20000224-1.c */
std::unordered_set<phi_info *> marked_phi_nodes{};
- // Phi will not be prelive
auto prelive_insns = rtl_ssa_dce_prelive(marked);
+ /* Extract uses from prelive insns to worklist */
auto_vec<set_info *> worklist{};
for (insn_info * insn : prelive_insns) {
for (auto&& use : insn->uses()) {
set_info* set = use->def();
- if (set) {
+ if (set)
worklist.safe_push(set);
- }
}
}
while (!worklist.is_empty()) {
set_info* set = worklist.pop();
insn_info* insn = set->insn();
- if (!insn) {
+ if (!insn)
continue;
- }
-
- /*
- * TODO : a phi insn might be visited more times due to having more phi
nodes
- * Either we have to mark phi nodes or do not mark phi insn
- */
+ /* A phi insn might be visited more times because of having more phi nodes
+ The phi insn is never marked, only phi nodes (phi_info) */
auto uid = insn->uid();
- if ((marked.count(insn) > 0) && !insn->is_phi()) {
+ if ((marked.count(insn) > 0) && !insn->is_phi())
continue;
- }
marked.emplace(insn);
use_array uses = insn->uses();
if (insn->is_phi()) {
- // Each phi node has a unique uid, yeeey
- // So, only one bitmap (with shift) in needed.
+ /* Each phi node has a unique uid, so only one bitmap (with shift) in
+ might be used. */
phi_info* pi = as_a<phi_info *> (set);
auto pi_uid = pi->uid();
- if (marked_phi_nodes.count(pi) > 0) {
+ if (marked_phi_nodes.count(pi) > 0)
continue;
- }
+
marked_phi_nodes.emplace(pi);
uses = pi->inputs();
}
if (dump_file)
- fprintf(dump_file, " Adding insn %d to worklist - mark\n", insn->uid());
+ fprintf(dump_file, "Adding insn %d to worklist\n", insn->uid());
for (use_info * use : uses) {
set_info* parent_set = use->def();
- if (!parent_set) {
+ if (!parent_set)
continue;
- }
worklist.safe_push(parent_set);
}
}
- // TODO : control dependence
return marked;
}
static void
rtl_ssa_dce_sweep(std::unordered_set<insn_info *> marked)
{
- // we can get the number of items in the set and create an array of changes
- // which will hopefully have constructor for array_slice<insn_info *>
+ /* We can get the number of items in the `marked` set and create an array
+ of changes with appropriate size */
auto_vec<insn_change> to_delete;
for (insn_info * insn : crtl->ssa->all_insns()) {
- // artificial and marked insns cannot be deleted
+ /* artificial and marked insns cannot be deleted */
if (insn->is_artificial() || marked.count(insn) > 0)
continue;
auto change = insn_change::delete_insn(insn);
to_delete.safe_push(change);
if (dump_file)
- fprintf(dump_file, " Sweeping insn %d\n", insn->uid());
- // crtl->ssa->change_insn(change);
+ fprintf(dump_file, "Sweeping insn %d\n", insn->uid());
+ /* crtl->ssa->change_insn(change); */
}
auto attempt = crtl->ssa->new_change_attempt ();
@@ -1709,19 +1589,21 @@ rtl_ssa_dce_sweep(std::unordered_set<insn_info *>
marked)
}
gcc_assert (crtl->ssa->verify_insn_changes(changes));
- // segfault: gcc.c-torture/execute/20000224-1.c
+ /* segfault: gcc.c-torture/execute/20000224-1.c */
crtl->ssa->change_insns(changes);
}
+// WIP
static void
rtl_ssa_dce_transform_insns_to_debug() {
std::unordered_set<int> is_debug;
- // TODO : make sure, that phi_nodes have unique id from all insns
// Should we use ssa when modifing insns? if yes, we want in-place replace
- // chceme prochazet v post orderu, abychom nejdrive zpracovali zavislosti a
pak az definici
- // nelze jen menit instrukce, protoze musime informaci propagovat pres phi
node
- // We check, if insns that use a definition from current insn are all debug
+ /* chceme prochazet v post orderu, abychom nejdrive zpracovali zavislosti
+ a pak az definici nelze jen menit instrukce, protoze musime informaci
+ propagovat pres phi node */
+ /* We check, whether all insns that use a definition from the current insn
+ are only debug insns */
for (insn_info * insn : crtl->ssa->reverse_all_insns()) {
if (insn->is_debug_insn()) { // phi is never debug
// TODO : store info about this insn
@@ -1803,36 +1685,36 @@ rtl_ssa_dce_done()
delete crtl->ssa;
crtl->ssa = nullptr;
-
- if (dump_file)
- fprintf(dump_file, "\nFinished running rtl_ssa_dce\n\n");
}
static unsigned int
rtl_ssa_dce()
{
- // for (int i = 0; i < FIRST_VIRTUAL_REGISTER; ++i) {
- // if (global_regs[i] > 0)
- // std::cerr << "Global reg needed: " << i << '\n';
- // if (fixed_regs[i] > 0)
- // std::cerr << "Fixed reg: " << i << '\n';
- // }
- // std::cerr << "RTL SSA BEGIN\n" << std::endl;
rtl_ssa_dce_init();
std::unordered_set<insn_info *> marked = rtl_ssa_dce_mark();
rtl_ssa_dce_sweep(marked);
- std::cerr << "\033[31m" << "SSA debug start" << "\033[0m" << "\n";
- debug (crtl->ssa);
- for (insn_info * insn : crtl->ssa->all_insns()) {
- if (insn->is_artificial())
- continue;
- debug(insn->rtl());
- }
- std::cerr << "\033[31m" << "SSA debug end" << "\033[0m" << "\n";
- rtl_ssa_dce_done();
- // if (delete_trivially_dead_insns(get_insns (), max_reg_num ())) {
- // std::cerr << "\033[31m" << "rtl_ssa_dce did not delete everything :("
<< "\033[0m" << "\n";
+ // std::cerr << "\033[31m" << "SSA debug start" << "\033[0m" << "\n";
+ // debug (crtl->ssa);
+ // for (insn_info * insn : crtl->ssa->all_insns()) {
+ // if (insn->is_artificial())
+ // continue;
+ // debug(insn->rtl());
// }
+ // std::cerr << "\033[31m" << "SSA debug end" << "\033[0m" << "\n";
+ rtl_ssa_dce_done();
+
+ /* We need to perform some kind of reset_unmarked_insns_debug_uses
+ to be able to reproduce ud_dce - now only 4 tests are falling
+ because of debug_insn being dependent on parallel with set flags
+ - gcc.c-torture/execute/20051215-1.c
+ - gcc.c-torture/execute/20100805-1.c
+ - gcc.c-torture/execute/pr39339.c
+ - gcc.c-torture/execute/pr47925.c */
+
+ /*
+ if (delete_trivially_dead_insns(get_insns (), max_reg_num ())) {
+ std::cerr << "\033[31m" << "rtl_ssa_dce did not delete everything :(" <<
"\033[0m" << "\n";
+ } */
return 0;
}
@@ -1872,7 +1754,7 @@ namespace
unsigned int execute(function *) final override { return rtl_ssa_dce(); }
- }; // class pass_fast_rtl_dce
+ }; // class pass_rtl_ssa_dce
} // namespace
