Skip to content
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

Subtype: minor optimization for simple_intersect #49477

Merged
merged 1 commit into from
Apr 25, 2023
Merged

Subtype: minor optimization for simple_intersect #49477

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
61 changes: 30 additions & 31 deletions src/jltypes.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -719,20 +719,6 @@ jl_value_t *simple_union(jl_value_t *a, jl_value_t *b)

int obviously_disjoint(jl_value_t *a, jl_value_t *b, int specificity);

static int simple_disjoint(jl_value_t *a, jl_value_t *b, int hasfree)
{
if (jl_is_uniontype(b)) {
jl_value_t *b1 = ((jl_uniontype_t *)b)->a, *b2 = ((jl_uniontype_t *)b)->b;
JL_GC_PUSH2(&b1, &b2);
int res = simple_disjoint(a, b1, hasfree) && simple_disjoint(a, b2, hasfree);
JL_GC_POP();
return res;
}
if (!hasfree && !jl_has_free_typevars(b))
return jl_has_empty_intersection(a, b);
return obviously_disjoint(a, b, 0);
}

jl_value_t *simple_intersect(jl_value_t *a, jl_value_t *b, int overesi)
{
// Unlike `Union`, we don't unwrap `UnionAll` here to avoid possible widening.
Expand All @@ -746,19 +732,31 @@ jl_value_t *simple_intersect(jl_value_t *a, jl_value_t *b, int overesi)
flatten_type_union(&b, 1, temp, &count, 0);
assert(count == nt);
size_t i, j;
int8_t *stemp = (int8_t *)alloca(count);
// first remove disjoint elements.
memset(stemp, 0, count);
for (i = 0; i < nta; i++) {
int hasfree = jl_has_free_typevars(temp[i]);
for (j = nta; j < nt; j++) {
if (!stemp[i] || !stemp[j]) {
int intersect = !hasfree && !jl_has_free_typevars(temp[j]);
if (!(intersect ? jl_has_empty_intersection(temp[i], temp[j]) : obviously_disjoint(temp[i], temp[j], 0)))
stemp[i] = stemp[j] = 1;
}
}
}
for (i = 0; i < nt; i++) {
if (simple_disjoint(temp[i], (i < nta ? b : a), jl_has_free_typevars(temp[i])))
temp[i] = NULL;
temp[i] = stemp[i] ? temp[i] : NULL;
}
// then check subtyping.
// stemp[k] == -1 : ∃i temp[k] >:ₛ temp[i]
// stemp[k] == 1 : ∃i temp[k] == temp[i]
// stemp[k] == 2 : ∃i temp[k] <:ₛ temp[i]
int8_t *stemp = (int8_t *)alloca(count);
memset(stemp, 0, count);
int all_disjoint = 1, subs[2] = {1, 1}, rs[2] = {1, 1};
for (i = 0; i < nta; i++) {
if (temp[i] == NULL) continue;
all_disjoint = 0;
int hasfree = jl_has_free_typevars(temp[i]);
for (j = nta; j < nt; j++) {
if (temp[j] == NULL) continue;
Expand All @@ -778,22 +776,23 @@ jl_value_t *simple_intersect(jl_value_t *a, jl_value_t *b, int overesi)
}
}
}
int subs[2] = {1, 1}, rs[2] = {1, 1};
for (i = 0; i < nt; i++) {
subs[i >= nta] &= (temp[i] == NULL || stemp[i] > 0);
rs[i >= nta] &= (temp[i] != NULL && stemp[i] > 0);
}
// return a(b) if a(b) <: b(a)
if (rs[0]) {
JL_GC_POP();
return a;
}
if (rs[1]) {
JL_GC_POP();
return b;
if (!all_disjoint) {
for (i = 0; i < nt; i++) {
subs[i >= nta] &= (temp[i] == NULL || stemp[i] > 0);
rs[i >= nta] &= (temp[i] != NULL && stemp[i] > 0);
}
// return a(b) if a(b) <: b(a)
if (rs[0]) {
JL_GC_POP();
return a;
}
if (rs[1]) {
JL_GC_POP();
return b;
}
}
// return `Union{}` for `merge_env` if we can't prove `<:` or `>:`
if (!overesi && !subs[0] && !subs[1]) {
if (all_disjoint || (!overesi && !subs[0] && !subs[1])) {
JL_GC_POP();
return jl_bottom_type;
}
Expand Down