https://gcc.gnu.org/g:8dd2f1ee16fb9ec05ef5c5370e33b0acb946e94d
commit 8dd2f1ee16fb9ec05ef5c5370e33b0acb946e94d
Author: Ondřej Machota <ondrejmach...@gmail.com>
Date: Fri Mar 14 14:04:39 2025 +0100
rtl-ssa-dce: phis are marked correctly
Diff:
---
gcc/dce.cc | 112 ++++++++++++++-----------------------------------------------
1 file changed, 25 insertions(+), 87 deletions(-)
diff --git a/gcc/dce.cc b/gcc/dce.cc
index cfa58f21dc03..58d763314778 100644
--- a/gcc/dce.cc
+++ b/gcc/dce.cc
@@ -1473,7 +1473,7 @@ bool is_rtx_insn_prelive(rtx_insn *insn) {
return true;
rtx body = PATTERN(insn);
- if (GET_CODE(body) == CLOBBER) //
~/Documents/gcc/gcc/testsuite/gcc.c-torture/compile/20000605-1.c
+ if (GET_CODE(body) == CLOBBER) //
gcc/gcc/testsuite/gcc.c-torture/compile/20000605-1.c
return true;
if (side_effects_with_mem(body) || can_throw_internal(body))
@@ -1588,12 +1588,18 @@ rtl_ssa_dce_prelive(std::unordered_set<insn_info *>
&marked)
static std::unordered_set<insn_info *>
rtl_ssa_dce_mark()
{
+ std::unordered_set<set_info *> marked_sets{};
+
+
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
+ std::unordered_set<phi_info *> marked_phi_nodes{};
+ // Phi will not be prelive
auto worklist = rtl_ssa_dce_prelive(marked);
auto_vec<set_info *> worklist_new{};
for (auto && item : worklist) {
insn_info * insn = item;
- std::cerr << "cp Current: " << insn->uid() << '\n';
+ // std::cerr << "cp Current: " << insn->uid() << '\n';
for (auto&& use : insn->uses()) {
set_info* set = use->def();
if (set) {
@@ -1613,20 +1619,26 @@ rtl_ssa_dce_mark()
* 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
*/
- std::cerr << "Current: " << insn->uid() << '\n';
+ // std::cerr << "Current: " << insn->uid() << '\n';
// if (insn->uid() == -21) {
// std::cerr << "Insn -21 phi? " << insn->is_phi() << '\n';
// }
- if ((marked.count(insn) > 0)) {
+ if ((marked.count(insn) > 0) && !insn->is_phi()) {
continue;
}
+ // std::cout << insn->uid() << " not skipped\n";
+
marked.emplace(insn);
use_array uses = insn->uses();
if (insn->is_phi()) {
phi_info* pi = as_a<phi_info *> (set);
+ if (marked_phi_nodes.count(pi) > 0) {
+ continue;
+ }
+ marked_phi_nodes.emplace(pi);
uses = pi->inputs();
}
@@ -1644,80 +1656,6 @@ rtl_ssa_dce_mark()
}
}
- // if (dump_file)
- // fprintf(dump_file, "Finished inherently live, marking parents\n");
- // while (!worklist.is_empty())
- // {
- // insn_info *insn = worklist.pop();
- // use_array uses = insn->uses();
- // if (insn->is_phi()) {
- // std::cerr << "Phi : "<< insn->uid() << " - uses: " <<
insn->num_uses() << ", defs:" << insn->num_defs() << '\n';
- // for (auto&& use : uses) {
- // debug(use);
- // std::cerr << '\n';
- // }
- // } else if (insn->is_artificial()) {
- // std::cerr << "Artificial " << insn->uid() << " - uses: " <<
insn->num_uses() << ", defs:" << insn->num_defs() << '\n';
- // for (auto&& use : uses) {
- // debug(use);
- // std::cerr << '\n';
- // }
- // }
-
- // if (dump_file)
- // fprintf(dump_file, "Looking at: %d, uses: %d\n", insn->uid(),
uses.size());
-
- // //std::cerr << "Insn: " << insn->uid() << ", uses: " << uses.size() <<
'\n';
- // std::cerr << "Current: " << insn->uid() << '\n';
- // for (size_t i = 0; i < uses.size(); i++)
- // {
- // // debug(uses[i]);
- // use_info* use = uses[i];
- // // debug(use->def());
- // // if (use->def() != nullptr) {
- // // std::cerr << use->def()->insn()->uid() << '\n';
- // // }
- // // std::cerr << '\n';
- // // debug(use);
- // // std::cerr << '\n';
-
- // set_info* set = use->def();
- // if (!set) {
- // continue;
- // }
- // insn_info *parent_insn = set->insn();
- // if (!parent_insn) {
- // continue;
- // }
- // // if (parent_insn->is_phi()) { // this is weird...
- // // // debug(use->def());
- // // phi_info * pi = as_a<phi_info *> (use->def());
- // // // std::cerr << "phi inputs: " << pi->num_inputs() << '\n';
- // // for (auto&& input: pi->inputs()) {
- // // use_info* phi_use = input;
- // // std::cerr << "Via phi insn: " << phi_use->def()->insn()->uid()
<< '\n';
- // // }
- // // }
- // int parent_insn_uid = parent_insn->uid();
- // // propage that some instruction in chain is live from bottom to top
- // if (dump_file)
- // fprintf(dump_file, "Trying to add: %d\n", parent_insn_uid);
- // // not yet marked
- // if (!(marked.count(parent_insn) > 0))
- // {
- // //std::cerr << "Adding: " << parent_insn_uid << " to worklist";
- // if (dump_file)
- // fprintf(dump_file, " Adding insn %d to worklist - mark\n",
parent_insn_uid);
-
-
- // worklist.safe_push(parent_insn);
- // marked.emplace(parent_insn);
- // }
- // }
-
- // auto bb = insn->bb();
- // }
-
// for (auto&& insn : marked) {
// if (dump_file)
// fprintf(dump_file, " Marked insn: %d\n", insn->uid());
@@ -1736,7 +1674,7 @@ 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 *>
auto attempt = crtl->ssa->new_change_attempt ();
- std::cerr << "Change attempt created successfully" << std::endl;
+ // std::cerr << "Change attempt created successfully" << std::endl;
for (insn_info *insn = crtl->ssa->first_insn(); insn; insn = next)
{
if (dump_file)
@@ -1754,7 +1692,7 @@ rtl_ssa_dce_sweep(std::unordered_set<insn_info *> marked)
// Skip artificial insns (or uid() < 0)
if (insn->is_real())
{
- std::cerr << "Insn: " << insn->uid() << " will be deleted\n";
+ // std::cerr << "Insn: " << insn->uid() << " will be deleted\n";
auto change = insn_change::delete_insn(insn);
// crtl->ssa->possibly_queue_changes(change);
to_delete.safe_push(change);
@@ -1763,20 +1701,20 @@ rtl_ssa_dce_sweep(std::unordered_set<insn_info *>
marked)
}
}
- std::cerr << "Selected unmarked insns" << std::endl;
+ // std::cerr << "Selected unmarked insns" << std::endl;
auto_vec<insn_change*> changes(to_delete.length());
for (size_t i = 0; i != to_delete.length(); ++i) {
changes.safe_push(&to_delete[i]);
}
- std::cerr << "Verification" << std::endl;
+ // std::cerr << "Verification" << std::endl;
if (crtl->ssa->verify_insn_changes(changes)) {
- std::cerr << "Changes are correct" << std::endl;
+ // std::cerr << "Changes are correct" << std::endl;
// segfault: gcc.c-torture/execute/20000224-1.c
crtl->ssa->change_insns(changes);
} else {
- std::cerr << "Changes are not correct\n";
+ // std::cerr << "Changes are not correct\n";
}
}
@@ -1784,13 +1722,13 @@ static unsigned int
rtl_ssa_dce()
{
rtl_ssa_dce_init();
- debug(crtl->ssa);
+ // debug(crtl->ssa);
//std::cerr << "Next phase: prelive + mark: \n";
std::unordered_set<insn_info *> marked = rtl_ssa_dce_mark();
- std::cerr << "Marking done\n";
+ // std::cerr << "Marking done\n";
rtl_ssa_dce_sweep(marked);
- std::cerr << "Sweeping done\n";
+ // std::cerr << "Sweeping done\n";
rtl_ssa_dce_done();
return 0;
