diff --git a/include/grpc/support/port_platform.h b/include/grpc/support/port_platform.h
index 69709f88502..93291a174da 100644
--- a/include/grpc/support/port_platform.h
+++ b/include/grpc/support/port_platform.h
@@ -179,6 +179,7 @@
 #ifndef _BSD_SOURCE
 #define _BSD_SOURCE
 #endif
+#define GPR_MSG_IOVLEN_TYPE int
 #if TARGET_OS_IPHONE
 #define GPR_PLATFORM_STRING "ios"
 #define GPR_CPU_IPHONE 1
diff --git a/src/core/iomgr/pollset_multipoller_with_poll_posix.c b/src/core/iomgr/pollset_multipoller_with_poll_posix.c
index f1bc60ba4e9..cae260cab0b 100644
--- a/src/core/iomgr/pollset_multipoller_with_poll_posix.c
+++ b/src/core/iomgr/pollset_multipoller_with_poll_posix.c
@@ -101,7 +101,8 @@ static void multipoll_with_poll_pollset_maybe_work(
     gpr_timespec now, int allow_synchronous_callback) {
   int timeout;
   int r;
-  size_t i, j, pfd_count, fd_count;
+  size_t i, j, fd_count;
+  nfds_t pfd_count;
   pollset_hdr *h;
   /* TODO(ctiller): inline some elements to avoid an allocation */
   grpc_fd_watcher *watchers;
diff --git a/src/core/iomgr/tcp_posix.c b/src/core/iomgr/tcp_posix.c
index 81f04494eb5..68f469c3681 100644
--- a/src/core/iomgr/tcp_posix.c
+++ b/src/core/iomgr/tcp_posix.c
@@ -61,6 +61,12 @@
 #define SENDMSG_FLAGS 0
 #endif
 
+#ifdef GPR_MSG_IOVLEN_TYPE
+typedef GPR_MSG_IOVLEN_TYPE msg_iovlen_type;
+#else
+typedef size_t msg_iovlen_type;
+#endif
+
 int grpc_tcp_trace = 0;
 
 typedef struct {
@@ -68,7 +74,7 @@ typedef struct {
   grpc_fd *em_fd;
   int fd;
   int finished_edge;
-  size_t iov_size; /* Number of slices to allocate per read attempt */
+  msg_iovlen_type iov_size; /* Number of slices to allocate per read attempt */
   size_t slice_size;
   gpr_refcount refcount;
 
@@ -265,7 +271,7 @@ static grpc_endpoint_op_status tcp_read(grpc_endpoint *ep,
 static grpc_endpoint_op_status tcp_flush(grpc_tcp *tcp) {
   struct msghdr msg;
   struct iovec iov[MAX_WRITE_IOVEC];
-  size_t iov_size;
+  msg_iovlen_type iov_size;
   ssize_t sent_length;
   size_t sending_length;
   size_t trailing;
diff --git a/src/core/support/cpu_posix.c b/src/core/support/cpu_posix.c
index 99484e37fbc..55d92c0555f 100644
--- a/src/core/support/cpu_posix.c
+++ b/src/core/support/cpu_posix.c
@@ -44,11 +44,11 @@
 
 static __thread char magic_thread_local;
 
-static int ncpus = 0;
+static long ncpus = 0;
 
 static void init_ncpus() {
   ncpus = sysconf(_SC_NPROCESSORS_ONLN);
-  if (ncpus < 1) {
+  if (ncpus < 1 || ncpus > GPR_UINT32_MAX) {
     gpr_log(GPR_ERROR, "Cannot determine number of CPUs: assuming 1");
     ncpus = 1;
   }
@@ -57,7 +57,7 @@ static void init_ncpus() {
 unsigned gpr_cpu_num_cores(void) {
   static gpr_once once = GPR_ONCE_INIT;
   gpr_once_init(&once, init_ncpus);
-  return ncpus;
+  return (unsigned)ncpus;
 }
 
 /* This is a cheap, but good enough, pointer hash for sharding things: */
@@ -71,7 +71,7 @@ unsigned gpr_cpu_current_cpu(void) {
      most code that's using this is using it to shard across work queues though,
      so here we use thread identity instead to achieve a similar though not
      identical effect */
-  return shard_ptr(&magic_thread_local);
+  return (unsigned)shard_ptr(&magic_thread_local);
 }
 
 #endif /* GPR_CPU_POSIX */
diff --git a/src/core/support/log_posix.c b/src/core/support/log_posix.c
index 940ee20f151..021c4666d41 100644
--- a/src/core/support/log_posix.c
+++ b/src/core/support/log_posix.c
@@ -62,7 +62,7 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
   } else if ((size_t)ret <= sizeof(buf) - 1) {
     message = buf;
   } else {
-    message = allocated = gpr_malloc(ret + 1);
+    message = allocated = gpr_malloc((size_t)ret + 1);
     va_start(args, format);
     vsnprintf(message, ret + 1, format, args);
     va_end(args);
diff --git a/src/core/support/time_posix.c b/src/core/support/time_posix.c
index a2744002437..dcecff0d05d 100644
--- a/src/core/support/time_posix.c
+++ b/src/core/support/time_posix.c
@@ -108,8 +108,8 @@ gpr_timespec gpr_now(gpr_clock_type clock) {
       break;
     case GPR_CLOCK_MONOTONIC:
       now_dbl = (mach_absolute_time() - g_time_start) * g_time_scale;
-      now.tv_sec = now_dbl * 1e-9;
-      now.tv_nsec = now_dbl - now.tv_sec * 1e9;
+      now.tv_sec = (time_t)(now_dbl * 1e-9);
+      now.tv_nsec = (int)(now_dbl - ((double)now.tv_sec) * 1e9);
       break;
     case GPR_CLOCK_PRECISE:
       gpr_precise_clock_now(&now);