https://gcc.gnu.org/g:aecd918163914a09df0f619a9f3163dcadfaf425
commit aecd918163914a09df0f619a9f3163dcadfaf425
Author: Ondřej Machota <ondrejmach...@gmail.com>
Date: Sun Mar 9 20:59:45 2025 +0100
rtl-ssa: dce fix bad marked insn map passing
Diff:
---
gcc/dce.cc | 146 ++++++++++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 116 insertions(+), 30 deletions(-)
diff --git a/gcc/dce.cc b/gcc/dce.cc
index f51f27dbd143..9a217a795b76 100644
--- a/gcc/dce.cc
+++ b/gcc/dce.cc
@@ -1316,6 +1316,7 @@ bool sets_global_register(const_rtx rtx) {
}
// We should mark stack registers
+// use HARD_FRAME_POINTER_REGNUM, REGNO_PTR_FRAME_P
bool sets_global_register(rtx_insn* insn) {
rtx set = single_set(insn);
if (!set)
@@ -1370,21 +1371,55 @@ bool is_unary_mem_modification(rtx_code code) {
}
}
-bool is_rtx_insn_prelive(const_rtx rtx) {
- if (rtx == nullptr) {
- return false;
+bool is_rtx_insn_prelive(rtx_insn *insn) {
+ gcc_assert(insn != nullptr);
+
+ // TODO : handle calls correctly
+ if (CALL_P (insn)
+ /* We cannot delete pure or const sibling calls because it is
+ 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. */
+ && (RTL_CONST_OR_PURE_CALL_P (insn) && !RTL_LOOPING_CONST_OR_PURE_CALL_P
(insn))
+ /* Don't delete calls that may throw if we cannot do so. */
+ && can_delete_call (insn))
+ return true;
+ // return !find_call_stack_args (as_a <rtx_call_insn *> (insn), false,
fast, arg_stores);
+
+ // Jumps, notes, barriers should not be deleted
+ // According to the docs, rtl ssa does not contain noteS and barrierS
+ if (!NONJUMP_INSN_P (insn))
+ {
+ std::cerr << "found jump instruction\n";
+ debug(insn);
+ return true;
}
- auto code = GET_CODE(rtx);
- if (is_control_flow(code))
+ // Only rtx_insn should be handled here
+ auto code = GET_CODE(insn);
+ gcc_assert(code == 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))
return true;
+ /* TODO : What about call argumets? Accoring to the docs, for function
prologue the RTX_FRAME_RELATED_P
+ should 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))
+ return true;
+
+ // if (is_control_flow(code))
+ // return true;
+
// Mark set of a global register
- if (sets_global_register(rtx)) // check rtx_class with GET_RTX_CLASS if
RTX_ISNS and convert if needed
+ if (sets_global_register(insn)) // check rtx_class with GET_RTX_CLASS if
RTX_ISNS and convert if needed
return true;
- // Call is inside side_effects_p - how to mark parameter registers?
- if (volatile_refs_p(rtx) || can_throw_internal(rtx) || BARRIER_P(rtx) ||
code == PREFETCH)
+ rtx body = PATTERN(insn);
+ if (side_effects_p(body) || can_throw_internal(body))
return true;
if (is_unary_mem_modification(code))
@@ -1394,21 +1429,34 @@ bool is_rtx_insn_prelive(const_rtx rtx) {
// Parallel is handled by volatile_refs_p
switch (code) {
-
- }
-
- const char *const fmt = GET_RTX_FORMAT (code);
- for (size_t i = 0; i < GET_RTX_LENGTH(code); ++i) {
- if (fmt[i] == 'e' && is_rtx_insn_prelive(XEXP(rtx, i))) {
+ case MEM:
+ case ASM_INPUT:
+ case ASM_OPERANDS:
return true;
- } else if (fmt[i] == 'E') {
- for (size_t j = 0; j < XVECLEN(rtx, i); ++j) {
- if (is_rtx_insn_prelive(XVECEXP(rtx, i, j)))
- return true;
- }
- }
+
+ case PARALLEL:
+ for (int i = XVECLEN (body, 0) - 1; i >= 0; i--)
+ if (!deletable_insn_p_1 (XVECEXP (body, 0, i)))
+ return true;
+ return false;
+ break;
+
+ default:
+ break;
}
+ // const char *const fmt = GET_RTX_FORMAT (code);
+ // for (size_t i = 0; i < GET_RTX_LENGTH(code); ++i) {
+ // if (fmt[i] == 'e' && is_rtx_insn_prelive(XEXP(rtx, i))) {
+ // return true;
+ // } else if (fmt[i] == 'E') {
+ // for (size_t j = 0; j < XVECLEN(rtx, i); ++j) {
+ // if (is_rtx_insn_prelive(XVECEXP(rtx, i, j)))
+ // return true;
+ // }
+ // }
+ // }
+
return false;
}
@@ -1443,7 +1491,7 @@ bool is_prelive(insn_info *insn)
if (!INSN_P(rtl)) // This might be useless
return false;
- rtx pat = PATTERN(rtl); // if we use this instead of rtl, then rtl notes
wont be checked
+ return is_rtx_insn_prelive(rtl);
// TODO : join if statements
// We need to describe all possible prelive instructions, a list of all the
instructions is inside `rtl.def`
@@ -1461,7 +1509,7 @@ bool is_prelive(insn_info *insn)
std::cerr << "Prelive: " << GET_RTX_NAME(code) << '\n';
// debug(insn);
debug(rtl);
- if (volatile_refs_p(rtl) || can_throw_internal(rtl) || BARRIER_P(rtl) ||
code == PREFETCH)
+ if (side_effects_p(rtl) || can_throw_internal(rtl) || BARRIER_P(rtl) || code
== PREFETCH)
return true;
if (code == PARALLEL) {
@@ -1496,7 +1544,7 @@ rtl_ssa_dce_done()
}
static void
-rtl_ssa_dce_mark_live(insn_info *info, vec<insn_info *> &worklist,
std::unordered_set<insn_info *> marked)
+rtl_ssa_dce_mark_live(insn_info *info, vec<insn_info *> &worklist,
std::unordered_set<insn_info *> &marked)
{
int info_uid = info->uid();
if (dump_file)
@@ -1507,7 +1555,7 @@ 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)
+rtl_ssa_dce_prelive(std::unordered_set<insn_info *> &marked)
{
insn_info *next;
auto_vec<insn_info *> worklist;
@@ -1542,9 +1590,10 @@ rtl_ssa_dce_prelive(std::unordered_set<insn_info *>
marked)
return worklist;
}
-static void
-rtl_ssa_dce_mark(std::unordered_set<insn_info *> marked)
+static std::unordered_set<insn_info *>
+rtl_ssa_dce_mark()
{
+ std::unordered_set<insn_info *> marked{};
auto worklist = rtl_ssa_dce_prelive(marked);
if (dump_file)
@@ -1577,6 +1626,7 @@ rtl_ssa_dce_mark(std::unordered_set<insn_info *> marked)
}
// TODO : control dependence
+ return marked;
}
static void
@@ -1588,6 +1638,7 @@ rtl_ssa_dce_sweep(std::unordered_set<insn_info *> marked)
// it might be better to iterate over `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 *>
+ auto attempt = crtl->ssa->new_change_attempt ();
for (insn_info *insn = crtl->ssa->first_insn(); insn; insn = next)
{
if (dump_file)
@@ -1619,7 +1670,7 @@ rtl_ssa_dce_sweep(std::unordered_set<insn_info *> marked)
if (crtl->ssa->verify_insn_changes(changes)) {
std::cerr << "Changes are correct\n";
- // crtl->ssa->change_insns(changes);
+ crtl->ssa->change_insns(changes);
} else {
std::cerr << "Changes are not correct\n";
}
@@ -1630,11 +1681,46 @@ rtl_ssa_dce()
{
// I can do something like invert phi uid and shift it
// unordered_set seems to be the easiest option
- std::unordered_set<insn_info *> marked;
rtl_ssa_dce_init();
- debug(crtl->ssa);
+
+ for (rtl_ssa::bb_info* bb : crtl->ssa->bbs()) {
+ // debug(bb);
+ std::cerr << "BASIC BLOCK: " << bb->index() << '\n';
+ std::cerr << "PRINTING INSNS:\n";
+ for (rtl_ssa::insn_info* insn : bb->all_insns()) {
+ std::cerr << "PRINTING INSN\n";
+ debug(insn);
+ if (insn->is_real()) {
+ std::cerr << "RTL PART\n";
+ debug(insn->rtl());
+ } else {
+ std::cerr << "NON REAL INSN\n";
+ }
+
+ rtl_ssa::use_array ua = insn->uses();
+ std::cerr << "USES\n";
+ for (size_t i = 0; i < ua.size(); i++)
+ {
+ std::cerr << "USE: " << i << '\n';
+ ua[i]->def();
+ debug(ua[i]->insn());
+ }
+
+ // rtl_ssa::def_array df = insn->defs();
+ // std::cerr << "DEFS\n";
+ // for (size_t i = 0; i < df.size(); i++)
+ // {
+ // std::cerr << "DEF: " << i << '\n';
+ // debug(df[i]->insn());
+ // }
+ }
+
+ std::cerr << "\n\n\n";
+ }
+
+ // debug(crtl->ssa);
std::cerr << "Next phase: prelive + mark: \n";
- rtl_ssa_dce_mark(marked);
+ std::unordered_set<insn_info *> marked = rtl_ssa_dce_mark();
rtl_ssa_dce_sweep(marked);
rtl_ssa_dce_done();
