diff --git a/cord/tests/de.c b/cord/tests/de.c
index 7d27537b6..87273661d 100644
--- a/cord/tests/de.c
+++ b/cord/tests/de.c
@@ -80,18 +80,20 @@
 
 /* List of line number to position mappings, in descending order. */
 /* There may be holes.                                            */
-typedef struct LineMapRep {
+struct LineMapRep {
   int line;
   size_t pos;
   struct LineMapRep *previous;
-} * line_map;
+};
+typedef struct LineMapRep *line_map;
 
-/* List of file versions, one per edit operation */
-typedef struct HistoryRep {
+/* List of file versions, one per edit operation. */
+struct HistoryRep {
   CORD file_contents;
   struct HistoryRep *previous;
-  line_map map; /* Invalid for first record "now" */
-} * history;
+  line_map map; /* invalid for the first record "now" */
+};
+typedef struct HistoryRep *history;
 
 history now = 0;
 CORD current;             /* == now -> file_contents.     */
diff --git a/finalize.c b/finalize.c
index af1958704..e77c3f517 100644
--- a/finalize.c
+++ b/finalize.c
@@ -27,7 +27,7 @@ typedef void (*finalization_mark_proc)(ptr_t /* finalizable_obj_ptr */);
 
 #  define HASH3(addr, size, log_size)                               \
     ((size_t)((ADDR(addr) >> 3) ^ (ADDR(addr) >> (3 + (log_size)))) \
-     & ((size)-1))
+     & ((size) - (size_t)1))
 #  define HASH2(addr, log_size) HASH3(addr, (size_t)1 << (log_size), log_size)
 
 struct hash_chain_entry {
diff --git a/include/gc/cord_pos.h b/include/gc/cord_pos.h
index 835ad4c38..60576a64a 100644
--- a/include/gc/cord_pos.h
+++ b/include/gc/cord_pos.h
@@ -120,7 +120,8 @@ CORD_API void CORD__prev(CORD_pos);
 
 /* Advance position by n characters; n should be positive and less  */
 /* than CORD_pos_chars_left(p).                                     */
-#  define CORD_pos_advance(p, n) ((p)[0].cur_pos += (n)-1, CORD_next(p))
+#  define CORD_pos_advance(p, n) \
+    ((p)[0].cur_pos += (n) - (size_t)1, CORD_next(p))
 
 /* Address of the current character in cache.   */
 #  define CORD_pos_cur_char_addr(p) \
diff --git a/include/gc/gc.h b/include/gc/gc.h
index 7e00d0409..2e19a21a2 100644
--- a/include/gc/gc.h
+++ b/include/gc/gc.h
@@ -2316,11 +2316,11 @@ GC_API void *GC_CALL GC_find_limit(void * /* start */, int /* up */);
 
 #if defined(GC_INITIAL_HEAP_SIZE) && !defined(CPPCHECK)
 /* Set heap size to the desired value at start-up */
-#  define GC_INIT_CONF_INITIAL_HEAP_SIZE                      \
-    {                                                         \
-      size_t heap_size = GC_get_heap_size();                  \
-      if (heap_size < (GC_INITIAL_HEAP_SIZE))                 \
-        (void)GC_expand_hp((GC_INITIAL_HEAP_SIZE)-heap_size); \
+#  define GC_INIT_CONF_INITIAL_HEAP_SIZE                                  \
+    {                                                                     \
+      size_t heap_size = GC_get_heap_size();                              \
+      if (heap_size < (size_t)(GC_INITIAL_HEAP_SIZE))                     \
+        (void)GC_expand_hp(((size_t)(GC_INITIAL_HEAP_SIZE)) - heap_size); \
     }
 #else
 #  define GC_INIT_CONF_INITIAL_HEAP_SIZE /* empty */
diff --git a/include/gc/gc_inline.h b/include/gc/gc_inline.h
index e5f753b72..4ce06fb20 100644
--- a/include/gc/gc_inline.h
+++ b/include/gc/gc_inline.h
@@ -167,7 +167,7 @@ GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void *GC_CALL
             GC_end_stubborn_change(my_fl);                                \
             GC_reachable_here(next);                                      \
           }                                                               \
-          GC_ASSERT(GC_size(result) >= GC_GRANULE_BYTES * (lg));          \
+          GC_ASSERT(GC_size(result) >= GC_RAW_BYTES_FROM_INDEX(lg));      \
           GC_ASSERT((k) == GC_I_PTRFREE                                   \
                     || 0 /* NULL */ == ((void **)result)[1]);             \
           break;                                                          \
@@ -188,7 +188,7 @@ GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void *GC_CALL
                                  k, my_fl);                               \
           my_entry = *my_fl;                                              \
           if (0 /* NULL */ == my_entry) {                                 \
-            result = (*GC_get_oom_fn())(GC_GRANULE_BYTES * (lg));         \
+            result = (*GC_get_oom_fn())(GC_RAW_BYTES_FROM_INDEX(lg));     \
             break;                                                        \
           }                                                               \
         }                                                                 \
@@ -203,12 +203,13 @@ GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void *GC_CALL
 /* allocator lock.  The caller is responsible for supplying a cleared   */
 /* tiny_fl free-list array.  For single-threaded applications, this may */
 /* be a global array.                                                   */
-#define GC_MALLOC_WORDS_KIND(result, n, tiny_fl, k, init)                 \
-  do {                                                                    \
-    size_t lg = GC_PTRS_TO_WHOLE_GRANULES(n);                             \
-                                                                          \
-    GC_FAST_MALLOC_GRANS(result, lg, tiny_fl, 0 /* num_direct */, k,      \
-                         GC_malloc_kind((lg)*GC_GRANULE_BYTES, k), init); \
+#define GC_MALLOC_WORDS_KIND(result, n, tiny_fl, k, init)                \
+  do {                                                                   \
+    size_t lg = GC_PTRS_TO_WHOLE_GRANULES(n);                            \
+                                                                         \
+    GC_FAST_MALLOC_GRANS(result, lg, tiny_fl, 0 /* num_direct */, k,     \
+                         GC_malloc_kind(GC_RAW_BYTES_FROM_INDEX(lg), k), \
+                         init);                                          \
   } while (0)
 
 #define GC_MALLOC_WORDS(result, n, tiny_fl)             \
diff --git a/include/private/dbg_mlc.h b/include/private/dbg_mlc.h
index 5c2322d7f..5225c5c62 100644
--- a/include/private/dbg_mlc.h
+++ b/include/private/dbg_mlc.h
@@ -177,8 +177,9 @@ GC_INNER int GC_has_other_debug_info(ptr_t base);
       (((GC_uintptr_t)GC_cptr_load((volatile ptr_t *)(base)) & 1) != 0 \
        && GC_has_other_debug_info(base) > 0)
 #  else
-#    define GC_HAS_DEBUG_INFO(base) \
-      ((*(GC_uintptr_t *)(base)&1) != 0 && GC_has_other_debug_info(base) > 0)
+#    define GC_HAS_DEBUG_INFO(base)         \
+      (((*(GC_uintptr_t *)(base)) & 1) != 0 \
+       && GC_has_other_debug_info(base) > 0)
 #  endif
 #else
 #  define GC_HAS_DEBUG_INFO(base) (GC_has_other_debug_info(base) > 0)
diff --git a/include/private/gc_priv.h b/include/private/gc_priv.h
index fbc198aac..a064d340b 100644
--- a/include/private/gc_priv.h
+++ b/include/private/gc_priv.h
@@ -929,10 +929,10 @@ EXTERN_C_BEGIN
 #endif
 
 #define BYTES_TO_GRANULES(lb) ((lb) / GC_GRANULE_BYTES)
-#define GRANULES_TO_BYTES(lg) ((lg)*GC_GRANULE_BYTES)
+#define GRANULES_TO_BYTES(lg) (GC_GRANULE_BYTES * (lg))
 #define BYTES_TO_PTRS(lb) ((lb) / sizeof(ptr_t))
 #define PTRS_TO_BYTES(lpw) ((lpw) * sizeof(ptr_t))
-#define GRANULES_TO_PTRS(lg) ((lg)*GC_GRANULE_PTRS)
+#define GRANULES_TO_PTRS(lg) (GC_GRANULE_PTRS * (lg))
 
 /* Convert size in bytes to that in pointers rounding up (but   */
 /* not adding extra byte at end).                               */
@@ -2032,7 +2032,7 @@ GC_INNER void GC_push_all_register_sections(
 #  define MARK_BIT_OFFSET(sz) BYTES_TO_GRANULES(sz)
 #  define FINAL_MARK_BIT(sz)                 \
     ((sz) > MAXOBJBYTES ? MARK_BITS_PER_HBLK \
-                        : BYTES_TO_GRANULES((sz)*HBLK_OBJS(sz)))
+                        : BYTES_TO_GRANULES(HBLK_OBJS(sz) * (sz)))
 #endif /* !MARK_BIT_PER_OBJ */
 
 /* Important internal collector routines.       */
@@ -2183,15 +2183,15 @@ ptr_t GC_save_regs_in_stack(void);
     } while (0)
 
 #  ifdef THREADS
-#    define PS_COMPUTE_ADJUSTED_OFS(padj_ps_ofs, ps_ofs, ofs_sz_ull)   \
-      do {                                                             \
-        if ((ofs_sz_ull) <= (ps_ofs) /* && ofs_sz_ull > 0 */)          \
-          ABORT_ARG2("Incorrect size of procedure stack",              \
-                     ": ofs= %lu, size= %lu", (unsigned long)(ps_ofs), \
-                     (unsigned long)(ofs_sz_ull));                     \
-        *(padj_ps_ofs) = (ps_ofs) > PS_SYSCALL_TAIL_BYTES              \
-                             ? (ps_ofs)-PS_SYSCALL_TAIL_BYTES          \
-                             : 0;                                      \
+#    define PS_COMPUTE_ADJUSTED_OFS(padj_ps_ofs, ps_ofs, ofs_sz_ull)      \
+      do {                                                                \
+        if ((ofs_sz_ull) <= (ps_ofs) /* && ofs_sz_ull > 0 */)             \
+          ABORT_ARG2("Incorrect size of procedure stack",                 \
+                     ": ofs= %lu, size= %lu", (unsigned long)(ps_ofs),    \
+                     (unsigned long)(ofs_sz_ull));                        \
+        *(padj_ps_ofs) = (ps_ofs) > (unsigned)PS_SYSCALL_TAIL_BYTES       \
+                             ? (ps_ofs) - (unsigned)PS_SYSCALL_TAIL_BYTES \
+                             : 0;                                         \
       } while (0)
 #  else
 /* A simplified variant of the above assuming ps_ofs is a zero const. */
@@ -3165,7 +3165,10 @@ GC_INNER word GC_compute_root_size(void);
     static_assert(expr, "static assertion failed: " #expr)
 #elif defined(static_assert) && !defined(CPPCHECK) \
     && (__STDC_VERSION__ >= 201112L)
-#  define GC_STATIC_ASSERT(expr) static_assert(expr, #  expr)
+#  define GC_STATIC_ASSERT(expr)                                        \
+    do { /* wrap into do-while for proper formatting by clang-format */ \
+      static_assert(expr, #expr);                                       \
+    } while (0)
 #elif defined(mips) && !defined(__GNUC__) && !defined(CPPCHECK)
 /* DOB: MIPSPro C gets an internal error taking the sizeof an array type.
    This code works correctly (ugliness is to avoid "unused var" warnings) */
diff --git a/include/private/gcconfig.h b/include/private/gcconfig.h
index 8a8a04bcd..3e5c42758 100644
--- a/include/private/gcconfig.h
+++ b/include/private/gcconfig.h
@@ -781,10 +781,10 @@ EXTERN_C_BEGIN
 #  define PTR_ALIGN_UP(p, b) __builtin_align_up(p, b)
 #else
 #  define PTR_ALIGN_DOWN(p, b) \
-    ((ptr_t)((GC_uintptr_t)(p) & ~(GC_uintptr_t)((b)-1)))
-#  define PTR_ALIGN_UP(p, b)                             \
-    ((ptr_t)(((GC_uintptr_t)(p) + (GC_uintptr_t)((b)-1)) \
-             & ~(GC_uintptr_t)((b)-1)))
+    ((ptr_t)((GC_uintptr_t)(p) & ~((GC_uintptr_t)(b) - (GC_uintptr_t)1)))
+#  define PTR_ALIGN_UP(p, b)                                           \
+    ((ptr_t)(((GC_uintptr_t)(p) + (GC_uintptr_t)(b) - (GC_uintptr_t)1) \
+             & ~((GC_uintptr_t)(b) - (GC_uintptr_t)1)))
 #endif
 
 /* If available, we can use __builtin_unwind_init() to push the     */
@@ -1446,7 +1446,7 @@ extern int _etext, _end;
 #    ifndef USE_MMAP
 #      define USE_MMAP 1
 #    endif
-#    define MAP_FAILED (void *)((GC_uintptr_t)-1)
+#    define MAP_FAILED ((void *)(~(GC_uintptr_t)0))
 #    define HEAP_START ((word)0x40000000)
 #  endif /* DGUX */
 #  ifdef LINUX
@@ -2357,7 +2357,7 @@ LONG64 durango_get_stack_bottom(void);
 #    define PROT_EXEC 4
 #    define MAP_PRIVATE 2
 #    define MAP_FIXED 0x10
-#    define MAP_FAILED ((void *)-1)
+#    define MAP_FAILED ((void *)(~(GC_uintptr_t)0))
 #  endif
 #  ifdef MSWIN32
 #    define RETRY_GET_THREAD_CONTEXT
@@ -2471,9 +2471,9 @@ void *emmalloc_memalign(size_t align, size_t lb);
 #  ifdef WASI
 #    define OS_TYPE "WASI"
 extern char __global_base, __heap_base;
-#    define STACKBOTTOM ((ptr_t)&__global_base)
-#    define DATASTART ((ptr_t)&__global_base)
-#    define DATAEND ((ptr_t)&__heap_base)
+#    define DATASTART ((ptr_t)(&__global_base))
+#    define DATAEND ((ptr_t)(&__heap_base))
+#    define STACKBOTTOM DATASTART
 #    ifndef GC_NO_SIGSETJMP
 #      define GC_NO_SIGSETJMP 1 /* no support of signals */
 #    endif
@@ -3408,7 +3408,7 @@ extern ptr_t GC_data_start;
 #  define NEED_FIXUP_POINTER
 #elif defined(DYNAMIC_POINTER_MASK)
 #  define FIXUP_POINTER(p) \
-    (p = (ptr_t)(((word)(p)&GC_pointer_mask) << GC_pointer_shift))
+    (p = (ptr_t)((((word)(p)) & GC_pointer_mask) << GC_pointer_shift))
 #  undef POINTER_MASK
 #  undef POINTER_SHIFT
 #  define NEED_FIXUP_POINTER
diff --git a/include/private/pthread_support.h b/include/private/pthread_support.h
index 603f5d5da..5b98d2e95 100644
--- a/include/private/pthread_support.h
+++ b/include/private/pthread_support.h
@@ -60,7 +60,7 @@ typedef struct GC_NT_TIB_s GC_NT_TIB;
 #    endif
 #  endif
 
-typedef struct GC_StackContext_Rep {
+struct GC_StackContext_Rep {
 #  if defined(THREAD_SANITIZER) && defined(SIGNAL_BASED_STOP_WORLD)
   /* A dummy field to avoid TSan false positive about the race        */
   /* between GC_has_other_debug_info and GC_suspend_handler_inner     */
@@ -133,7 +133,8 @@ typedef struct GC_StackContext_Rep {
   /* Points to the "frame" data held in stack by the innermost          */
   /* GC_call_with_gc_active() of this stack (thread); may be NULL.      */
   struct GC_traced_stack_sect_s *traced_stack_sect;
-} * GC_stack_context_t;
+};
+typedef struct GC_StackContext_Rep *GC_stack_context_t;
 
 #  ifdef GC_WIN32_THREADS
 typedef DWORD thread_id_t;
@@ -150,7 +151,7 @@ typedef pthread_t thread_id_t;
 #    define THREAD_ID_TO_VPTR(id) PTHREAD_TO_VPTR(id)
 #  endif
 
-typedef struct GC_Thread_Rep {
+struct GC_Thread_Rep {
   union {
 #  if !defined(GC_NO_THREADS_DISCOVERY) && defined(GC_WIN32_THREADS)
     /* Updated without a lock.  We assert that each unused entry has  */
@@ -278,7 +279,8 @@ typedef struct GC_Thread_Rep {
   /* needed for GetThreadContext() to succeed.                        */
   word context_regs[PUSHED_REGS_COUNT];
 #  endif
-} * GC_thread;
+};
+typedef struct GC_Thread_Rep *GC_thread;
 
 #  if defined(GC_PTHREADS) || defined(GC_PTHREADS_PARAMARK)
 /* Convert an opaque pthread_t value to a pointer identifying the thread. */
diff --git a/include/private/thread_local_alloc.h b/include/private/thread_local_alloc.h
index 79765b2a3..fe95e1486 100644
--- a/include/private/thread_local_alloc.h
+++ b/include/private/thread_local_alloc.h
@@ -120,7 +120,7 @@ EXTERN_C_BEGIN
 /* allocation, equivalent to 0;                                     */
 /* - >=HBLKSIZE means pointer to nonempty free list.                */
 
-typedef struct thread_local_freelists {
+struct thread_local_freelists {
   /* Note: Preserve *_freelists names for some clients. */
   void *_freelists[THREAD_FREELISTS_KINDS][GC_TINY_FREELISTS];
 #  define ptrfree_freelists _freelists[PTRFREE]
@@ -133,7 +133,8 @@ typedef struct thread_local_freelists {
 
   /* Do not use local free lists for up to this much allocation.    */
 #  define DIRECT_GRANULES (HBLKSIZE / GC_GRANULE_BYTES)
-} * GC_tlfs;
+};
+typedef struct thread_local_freelists *GC_tlfs;
 
 #  if defined(USE_PTHREAD_SPECIFIC)
 #    define GC_getspecific pthread_getspecific
diff --git a/os_dep.c b/os_dep.c
index a3afcc7ab..3809da7c4 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -1226,8 +1226,9 @@ os_main_stackbottom(void)
     /* low while the initialization code is running.              */
     if ((ADDR(__libc_stack_end) & 0xfff) + 0x10 < 0x1000) {
       return __libc_stack_end + 0x10;
-    } /* Otherwise it's not safe to add 16 bytes and we fall      */
-      /* back to using /proc.                                     */
+    } else {
+      /* It is not safe to add 16 bytes.  Thus, fallback to using /proc. */
+    }
 #      elif defined(SPARC)
     /* Older versions of glibc for 64-bit SPARC do not set this   */
     /* variable correctly, it gets set to either zero or one.     */
@@ -4872,7 +4873,7 @@ GC_mprotect_thread(void *arg)
 #  endif
       }
     } /* switch */
-  }   /* for */
+  }
 }
 
 /* All this SIGBUS code should not be necessary.  All protection faults */
diff --git a/tests/gctest.c b/tests/gctest.c
index 2965407e2..06e7e9106 100644
--- a/tests/gctest.c
+++ b/tests/gctest.c
@@ -381,10 +381,13 @@ gcj_cons(sexpr x, sexpr y)
   size_t cnt = (size_t)AO_fetch_and_add1(&extra_count);
   const void *d = (cnt & 1) != 0 ? &gcj_class_struct1 : &gcj_class_struct2;
   size_t lb = sizeof(struct SEXPR) + sizeof(struct fake_vtable *);
-  void *r = (cnt & 2) != 0 ? GC_GCJ_MALLOC_IGNORE_OFF_PAGE(
-                lb + (cnt <= HBLKSIZE / 2 ? cnt : 0), d)
-                           : GC_GCJ_MALLOC(lb, d);
+  void *r;
 
+  if ((cnt & 2) != 0) {
+    r = GC_GCJ_MALLOC_IGNORE_OFF_PAGE(lb + (cnt <= HBLKSIZE / 2 ? cnt : 0), d);
+  } else {
+    r = GC_GCJ_MALLOC(lb, d);
+  }
   CHECK_OUT_OF_MEMORY(r);
   AO_fetch_and_add1(&collectable_count);
   /* Skip vtable pointer.     */
@@ -2022,7 +2025,8 @@ test_long_mult(void)
 #endif
 }
 
-#define NUMBER_ROUND_UP(v, bound) ((((v) + (bound)-1) / (bound)) * (bound))
+#define NUMBER_ROUND_UP(v, bound) \
+  ((((v) + (bound) - (unsigned)1) / (bound)) * (bound))
 
 static size_t initial_heapsize;
 
diff --git a/tests/trace.c b/tests/trace.c
index 152a6eb38..8f896120e 100644
--- a/tests/trace.c
+++ b/tests/trace.c
@@ -20,7 +20,9 @@
 struct treenode {
   struct treenode *x;
   struct treenode *y;
-} * root[10];
+};
+
+static struct treenode *root[10];
 
 static struct treenode *
 mktree(int i)
diff --git a/win32_threads.c b/win32_threads.c
index 4609b1672..a69a56ff0 100644
--- a/win32_threads.c
+++ b/win32_threads.c
@@ -645,7 +645,7 @@ GC_start_world(void)
 /* argument later and must not be used as the lower bound for sp      */
 /* check (since the stack may be bigger than 64 KiB).                 */
 #    define GC_wince_evaluate_stack_min(s) \
-      (ptr_t)(((word)(s)-1) & ~(word)0xFFFF)
+      (ptr_t)(((word)(s) - (word)1) & ~(word)0xFFFF)
 #  elif defined(GC_ASSERTIONS)
 #    define GC_dont_query_stack_min FALSE
 #  endif
@@ -1233,7 +1233,7 @@ GC_start_mark_threads_inner(void)
     handle = _beginthreadex(NULL /* security_attr */, MARK_THREAD_STACK_SIZE,
                             GC_mark_thread, NUMERIC_TO_VPTR(i), 0 /* flags */,
                             &thread_id);
-    if (EXPECT(!handle || handle == (GC_uintptr_t)-1L, FALSE)) {
+    if (EXPECT(!handle || handle == ~(GC_uintptr_t)0, FALSE)) {
       WARN("Marker thread %" WARN_PRIdPTR " creation failed\n",
            (GC_signed_word)i);
       /* Don't try to create other marker threads.                */