Skip to content

Improve liveness analysis by combining traversal passes #263

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Aug 26, 2025
Merged

Improve liveness analysis by combining traversal passes #263

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 34 additions & 5 deletions src/ssa.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1937,6 +1937,37 @@ void bb_reset_live_kill_idx(func_t *func, basic_block_t *bb)
bb->live_kill_idx = 0;
}

void add_live_gen(basic_block_t *bb, var_t *var);
void update_consumed(insn_t *insn, var_t *var);

/* Combined function to reset and solve locals in one pass */
void bb_reset_and_solve_locals(func_t *func, basic_block_t *bb)
{
UNUSED(func);

/* Reset live_kill index */
bb->live_kill_idx = 0;

/* Solve locals */
int i = 0;
for (insn_t *insn = bb->insn_list.head; insn; insn = insn->next) {
insn->idx = i++;

if (insn->rs1) {
if (!var_check_killed(insn->rs1, bb))
add_live_gen(bb, insn->rs1);
update_consumed(insn, insn->rs1);
}
if (insn->rs2) {
if (!var_check_killed(insn->rs2, bb))
add_live_gen(bb, insn->rs2);
update_consumed(insn, insn->rs2);
}
if (insn->rd && insn->opcode != OP_unwound_phi)
bb_add_killed_var(bb, insn->rd);
}
}

void add_live_gen(basic_block_t *bb, var_t *var)
{
if (var->is_global)
Expand Down Expand Up @@ -2065,16 +2096,14 @@ void liveness_analysis(void)
args->func = func;
args->bb = func->bbs;

/* Combined traversal: reset and solve locals in one pass */
func->visited++;
args->preorder_cb = bb_reset_live_kill_idx;
args->preorder_cb = bb_reset_and_solve_locals;
bb_forward_traversal(args);

/* Add function parameters as killed in entry block */
for (int i = 0; i < func->num_params; i++)
bb_add_killed_var(func->bbs, func->param_defs[i].subscripts[0]);

func->visited++;
args->preorder_cb = bb_solve_locals;
bb_forward_traversal(args);
}

for (func_t *func = FUNC_LIST.head; func; func = func->next) {
Expand Down