Splitting free block from end if block search direction is backward (currently, for short-term blocks).

src/liballocator/mem-heap.c

@@ -475,6 +475,35 @@ mem_heap_alloc_block (size_t size_in_bytes,           /**< size of region to all
   {
     MEM_HEAP_STAT_FREE_BLOCK_SPLIT ();
 
+    if (direction == MEM_DIRECTION_PREV)
+    {
+      prev_block_p = block_p;
+      uint8_t *block_end_p = (uint8_t*) block_p + found_block_size_in_chunks * MEM_HEAP_CHUNK_SIZE;
+      block_p = (mem_block_header_t*) (block_end_p - new_block_size_in_chunks * MEM_HEAP_CHUNK_SIZE);
+
+      VALGRIND_DEFINED_STRUCT(prev_block_p);
+
+      prev_block_p->neighbours[ MEM_DIRECTION_NEXT ] = mem_get_block_neighbour_field (prev_block_p,
+                                                                                      block_p);
+
+      VALGRIND_NOACCESS_STRUCT(prev_block_p);
+
+      if (next_block_p == NULL)
+      {
+        mem_heap.last_block_p = block_p;
+      }
+      else
+      {
+        VALGRIND_DEFINED_STRUCT(next_block_p);
+
+        next_block_p->neighbours[ MEM_DIRECTION_PREV ] = mem_get_block_neighbour_field (block_p,
+                                                                                        next_block_p);
+
+        VALGRIND_NOACCESS_STRUCT(next_block_p);
+      }
+    }
+    else
+    {
       uint8_t *new_free_block_first_chunk_p = (uint8_t*) block_p + new_block_size_in_chunks * MEM_HEAP_CHUNK_SIZE;
       mem_init_block_header (new_free_block_first_chunk_p,
                              0,
@@ -501,6 +530,7 @@ mem_heap_alloc_block (size_t size_in_bytes,           /**< size of region to all
 
       next_block_p = new_free_block_p;
     }
+  }
 
   mem_init_block_header ((uint8_t*) block_p,
                          size_in_bytes,