Adjusted get_median_from_3 and partitioner to also retrieve the pivot's index and check if either end of the partitioner has reached it to avoid comparing things with themselves

core/templates/sort_array.h

@@ -54,21 +54,24 @@ class SortArray {
 public:
 	Comparator compare;
 
-	inline const T &median_of_3(const T &a, const T &b, const T &c) const {
+	inline int64_t median_of_3_index(const T *p_ptr, int64_t a_index, int64_t b_index, int64_t c_index) const {
+		const T &a = p_ptr[a_index];
+		const T &b = p_ptr[b_index];
+		const T &c = p_ptr[c_index];
 		if (compare(a, b)) {
 			if (compare(b, c)) {
-				return b;
+				return b_index;
 			} else if (compare(a, c)) {
-				return c;
+				return c_index;
 			} else {
-				return a;
+				return a_index;
 			}
 		} else if (compare(a, c)) {
-			return a;
+			return a_index;
 		} else if (compare(b, c)) {
-			return c;
+			return c_index;
 		} else {
-			return b;
+			return b_index;
 		}
 	}
 
@@ -162,26 +165,27 @@ public:
 		}
 	}
 
-	inline int64_t partitioner(int64_t p_first, int64_t p_last, T p_pivot, T *p_array) const {
+	inline int64_t partitioner(int64_t p_first, int64_t p_last, int64_t p_pivot, T *p_array) const {
 		const int64_t unmodified_first = p_first;
 		const int64_t unmodified_last = p_last;
+		const T &pivot_element = p_array[p_pivot];
 
 		while (true) {
-			while (compare(p_array[p_first], p_pivot)) {
+			while (p_first != p_pivot && compare(p_array[p_first], pivot_element)) {
 				if constexpr (Validate) {
 					ERR_BAD_COMPARE(p_first == unmodified_last - 1);
 				}
 				p_first++;
 			}
 			p_last--;
-			while (compare(p_pivot, p_array[p_last])) {
+			while (p_last != p_pivot && compare(pivot_element, p_array[p_last])) {
 				if constexpr (Validate) {
 					ERR_BAD_COMPARE(p_last == unmodified_first);
 				}
 				p_last--;
 			}
 
-			if (!(p_first < p_last)) {
+			if (p_first >= p_last) {
 				return p_first;
 			}
 
@@ -202,10 +206,7 @@ public:
 			int64_t cut = partitioner(
 					p_first,
 					p_last,
-					median_of_3(
-							p_array[p_first],
-							p_array[p_first + (p_last - p_first) / 2],
-							p_array[p_last - 1]),
+					median_of_3_index(p_array, p_first, p_first + (p_last - p_first) / 2, p_last - 1),
 					p_array);
 
 			introsort(cut, p_last, p_array, p_max_depth);
@@ -226,10 +227,7 @@ public:
 			int64_t cut = partitioner(
 					p_first,
 					p_last,
-					median_of_3(
-							p_array[p_first],
-							p_array[p_first + (p_last - p_first) / 2],
-							p_array[p_last - 1]),
+					median_of_3_index(p_array, p_first, p_first + (p_last - p_first) / 2, p_last - 1),
 					p_array);
 
 			if (cut <= p_nth) {