diff --git a/src/ir.cpp b/src/ir.cpp
index a53367a324c630e30861416e4a20c822304b52c8..ce0e204e6378b512170f80cce5201ec90c971a11 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -21798,7 +21798,8 @@ static IrInstruction *ir_analyze_instruction_cmpxchg(IrAnalyze *ira, IrInstructi
         return ira->codegen->invalid_instruction;
     }
 
-    if (instr_is_comptime(casted_ptr) && instr_is_comptime(casted_cmp_value) && instr_is_comptime(casted_new_value)) {
+    if (instr_is_comptime(casted_ptr) && casted_ptr->value.data.x_ptr.mut != ConstPtrMutRuntimeVar &&
+        instr_is_comptime(casted_cmp_value) && instr_is_comptime(casted_new_value)) {
         zig_panic("TODO compile-time execution of cmpxchg");
     }
 
diff --git a/test/stage1/behavior/atomics.zig b/test/stage1/behavior/atomics.zig
index 1a941cf21c133a37da81d1d723fe20dc1c314461..8c4a186032b00b154498b9f3109722ebcade319e 100644
--- a/test/stage1/behavior/atomics.zig
+++ b/test/stage1/behavior/atomics.zig
@@ -100,3 +100,10 @@ test "cmpxchg with ignored result" {
 
     expectEqual(i32(5678), x);
 }
+
+var a_global_variable = u32(1234);
+
+test "cmpxchg on a global variable" {
+    _ = @cmpxchgWeak(u32, &a_global_variable, 1234, 42, .Acquire, .Monotonic);
+    expectEqual(u32(42), a_global_variable);
+}