refactor: don't use subtraction in qsort() comparison functions

src/nvim/channel.c

@@ -962,10 +962,11 @@ Dictionary channel_info(uint64_t id)
 }
 
 /// Simple int64_t comparison function for use with qsort()
-static int int64_t_cmp(const void *a, const void *b)
+static int int64_t_cmp(const void *pa, const void *pb)
 {
-  int64_t diff = *(int64_t *)a - *(int64_t *)b;
-  return (diff < 0) ? -1 : (diff > 0);
+  const int64_t a = *(const int64_t *)pa;
+  const int64_t b = *(const int64_t *)pb;
+  return a == b ? 0 : a > b ? 1 : -1;
 }
 
 Array channel_all_info(void)

src/nvim/decoration.c

@@ -673,10 +673,20 @@ int sign_item_cmp(const void *p1, const void *p2)
 {
   const SignItem *s1 = (SignItem *)p1;
   const SignItem *s2 = (SignItem *)p2;
-  int n = s2->sh->priority - s1->sh->priority;
 
-  return n ? n : (n = (int)(s2->id - s1->id))
-         ? n : (s2->sh->sign_add_id - s1->sh->sign_add_id);
+  if (s1->sh->priority != s2->sh->priority) {
+    return s1->sh->priority < s2->sh->priority ? 1 : -1;
+  }
+
+  if (s1->id != s2->id) {
+    return s1->id < s2->id ? 1 : -1;
+  }
+
+  if (s1->sh->sign_add_id != s2->sh->sign_add_id) {
+    return s1->sh->sign_add_id > s2->sh->sign_add_id ? 1 : -1;
+  }
+
+  return 0;
 }
 
 static const uint32_t sign_filter[4] = {[kMTMetaSignText] = kMTFilterSelect,

src/nvim/normal.c

@@ -375,7 +375,7 @@ static int nv_compare(const void *s1, const void *s2)
   if (c2 < 0) {
     c2 = -c2;
   }
-  return c1 - c2;
+  return c1 == c2 ? 0 : c1 > c2 ? 1 : -1;
 }
 
 /// Initialize the nv_cmd_idx[] table.

src/nvim/shada.c

@@ -1875,9 +1875,7 @@ static int compare_file_marks(const void *a, const void *b)
   const FileMarks *const *const b_fms = b;
   return ((*a_fms)->greatest_timestamp == (*b_fms)->greatest_timestamp
           ? 0
-          : ((*a_fms)->greatest_timestamp > (*b_fms)->greatest_timestamp
-             ? -1
-             : 1));
+          : ((*a_fms)->greatest_timestamp > (*b_fms)->greatest_timestamp ? -1 : 1));
 }
 
 /// Parse msgpack object that has given length

src/nvim/sign.c

@@ -172,20 +172,28 @@ int sign_cmp(const void *p1, const void *p2)
 {
   const MTKey *s1 = (MTKey *)p1;
   const MTKey *s2 = (MTKey *)p2;
-  int n = s1->pos.row - s2->pos.row;
 
-  if (n) {
-    return n;
+  if (s1->pos.row != s2->pos.row) {
+    return s1->pos.row > s2->pos.row ? 1 : -1;
   }
 
   DecorSignHighlight *sh1 = decor_find_sign(mt_decor(*s1));
   DecorSignHighlight *sh2 = decor_find_sign(mt_decor(*s2));
   assert(sh1 && sh2);
 
-  n = sh2->priority - sh1->priority;
+  if (sh1->priority != sh2->priority) {
+    return sh1->priority < sh2->priority ? 1 : -1;
+  }
 
-  return n ? n : (n = (int)(s2->id - s1->id))
-         ? n : (sh2->sign_add_id - sh1->sign_add_id);
+  if (s1->id != s2->id) {
+    return s1->id < s2->id ? 1 : -1;
+  }
+
+  if (sh1->sign_add_id != sh2->sign_add_id) {
+    return sh1->sign_add_id < sh2->sign_add_id ? 1 : -1;
+  }
+
+  return 0;
 }
 
 /// Delete the specified sign(s)

src/nvim/winfloat.c

@@ -233,7 +233,9 @@ void win_config_float(win_T *wp, WinConfig fconfig)
 
 static int float_zindex_cmp(const void *a, const void *b)
 {
-  return (*(win_T **)b)->w_float_config.zindex - (*(win_T **)a)->w_float_config.zindex;
+  int za = (*(win_T **)a)->w_float_config.zindex;
+  int zb = (*(win_T **)b)->w_float_config.zindex;
+  return za == zb ? 0 : za < zb ? 1 : -1;
 }
 
 void win_float_remove(bool bang, int count)