diff --git a/compiler/builtins/bitcode/src/utils.zig b/compiler/builtins/bitcode/src/utils.zig
index 810d75b27f..c9f03d897a 100644
--- a/compiler/builtins/bitcode/src/utils.zig
+++ b/compiler/builtins/bitcode/src/utils.zig
@@ -120,10 +120,16 @@ pub const IntWidth = enum(u8) {
     I128 = 9,
 };
 
+const USE_ATOMICS = false;
+
 pub fn increfC(ptr_to_refcount: *isize, amount: isize) callconv(.C) void {
     var refcount = ptr_to_refcount.*;
-    var masked_amount = if (refcount == REFCOUNT_MAX_ISIZE) 0 else amount;
-    ptr_to_refcount.* = refcount + masked_amount;
+    var masked_amount = if (refcount < REFCOUNT_MAX_ISIZE) amount else 0;
+    if (USE_ATOMICS) {
+        var last = @atomicRmw(isize, ptr_to_refcount, std.builtin.AtomicRmwOp.Add, masked_amount, std.builtin.AtomicOrder.Monotonic);
+    } else {
+        ptr_to_refcount.* = refcount + masked_amount;
+    }
 }
 
 pub fn decrefC(
@@ -169,13 +175,20 @@ inline fn decref_ptr_to_refcount(
     refcount_ptr: [*]isize,
     alignment: u32,
 ) void {
-    const refcount: isize = refcount_ptr[0];
     const extra_bytes = std.math.max(alignment, @sizeOf(usize));
-
-    if (refcount == REFCOUNT_ONE_ISIZE) {
-        dealloc(@ptrCast([*]u8, refcount_ptr) - (extra_bytes - @sizeOf(usize)), alignment);
-    } else if (refcount < 0) {
-        refcount_ptr[0] = refcount - 1;
+    if (USE_ATOMICS) {
+        var amount : isize = if (refcount_ptr[0] < REFCOUNT_MAX_ISIZE) 1 else 0;
+        var last = @atomicRmw(isize, &refcount_ptr[0], std.builtin.AtomicRmwOp.Sub, amount, std.builtin.AtomicOrder.Monotonic);
+        if (last == REFCOUNT_ONE_ISIZE) {
+            dealloc(@ptrCast([*]u8, refcount_ptr) - (extra_bytes - @sizeOf(usize)), alignment);
+        }
+    } else {
+        const refcount: isize = refcount_ptr[0];
+        if (refcount == REFCOUNT_ONE_ISIZE) {
+            dealloc(@ptrCast([*]u8, refcount_ptr) - (extra_bytes - @sizeOf(usize)), alignment);
+        } else if (refcount < REFCOUNT_MAX_ISIZE) {
+            refcount_ptr[0] = refcount - 1;
+        }
     }
 }