diff --git a/addr2line.c b/addr2line.c
index 54ee3eb1b9..e502c17961 100644
--- a/addr2line.c
+++ b/addr2line.c
@@ -1907,7 +1907,7 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
             uint32_t offset = __builtin_bswap32(arch->offset);
             /* fprintf(stderr,"%d: fat %d %x/%x %x/%x\n",__LINE__, i, mhp->cputype,mhp->cpusubtype, cputype,cpusubtype); */
             if (mhp->cputype == cputype &&
-                    (mhp->cpusubtype & ~CPU_SUBTYPE_MASK) == cpusubtype) {
+                    (cpu_subtype_t)(mhp->cpusubtype & ~CPU_SUBTYPE_MASK) == cpusubtype) {
                 p = file + offset;
                 file = p;
                 header = (struct LP(mach_header) *)p;
@@ -1980,9 +1980,9 @@ found_mach_header:
             {
                 struct symtab_command *cmd = (struct symtab_command *)lcmd;
                 struct LP(nlist) *nl = (struct LP(nlist) *)(file + cmd->symoff);
-                char *strtab = file + cmd->stroff, *sname;
+                char *strtab = file + cmd->stroff, *sname = 0;
                 uint32_t j;
-                uintptr_t saddr;
+                uintptr_t saddr = 0;
                 /* kprintf("[%2d]: %x/symtab %p\n", i, cmd->cmd, p); */
                 for (j = 0; j < cmd->nsyms; j++) {
                     uintptr_t symsize, d;
diff --git a/io.c b/io.c
index cec16ea5b7..893cabc248 100644
--- a/io.c
+++ b/io.c
@@ -10972,6 +10972,7 @@ static int
 nogvl_fcopyfile(struct copy_stream_struct *stp)
 {
     off_t cur, ss = 0;
+    const off_t src_offset = stp->src_offset;
     int ret;
 
     if (stp->copy_length >= (off_t)0) {
@@ -10987,7 +10988,7 @@ nogvl_fcopyfile(struct copy_stream_struct *stp)
     if (lseek(stp->dst_fd, 0, SEEK_CUR) > (off_t)0) /* if dst IO was already written */
         return 0;
 
-    if (stp->src_offset > (off_t)0) {
+    if (src_offset > (off_t)0) {
         off_t r;
 
         /* get current offset */
@@ -10999,7 +11000,7 @@ nogvl_fcopyfile(struct copy_stream_struct *stp)
         }
 
         errno = 0;
-        r = lseek(stp->src_fd, stp->src_offset, SEEK_SET);
+        r = lseek(stp->src_fd, src_offset, SEEK_SET);
         if (r < (off_t)0 && errno) {
             stp->error_no = errno;
             return 1;
@@ -11012,7 +11013,7 @@ nogvl_fcopyfile(struct copy_stream_struct *stp)
 
     if (ret == 0) { /* success */
         stp->total = ss;
-        if (stp->src_offset > (off_t)0) {
+        if (src_offset > (off_t)0) {
             off_t r;
             errno = 0;
             /* reset offset */
diff --git a/vm_trace.c b/vm_trace.c
index d778f244b1..da68a0a8de 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -418,7 +418,7 @@ VALUE
 rb_suppress_tracing(VALUE (*func)(VALUE), VALUE arg)
 {
     volatile int raised;
-    VALUE result = Qnil;
+    volatile VALUE result = Qnil;
     rb_execution_context_t *const ec = GET_EC();
     rb_vm_t *const vm = rb_ec_vm_ptr(ec);
     enum ruby_tag_type state;