diff --git a/src/ir.cpp b/src/ir.cpp
index f56ceaf4dd73643d85d71b105aaae411b1cfa8d8..a504d6c073856ae59cf62d75dfc4596852359546 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -9451,6 +9451,10 @@ static TypeTableEntry *ir_analyze_instruction_set_fn_visible(IrAnalyze *ira,
     return ira->codegen->builtin_types.entry_void;
 }
 
+static bool is_power_of_2(uint64_t x) {
+    return x != 0 && ((x & (~x + 1)) == x);
+}
+
 static TypeTableEntry *ir_analyze_instruction_set_global_align(IrAnalyze *ira,
         IrInstructionSetGlobalAlign *instruction)
 {
@@ -9461,7 +9465,10 @@ static TypeTableEntry *ir_analyze_instruction_set_global_align(IrAnalyze *ira,
     if (!ir_resolve_usize(ira, align_value, &scalar_align))
         return ira->codegen->builtin_types.entry_invalid;
 
-    // TODO error if not power of 2
+    if (!is_power_of_2(scalar_align)) {
+        ir_add_error(ira, instruction->value, buf_sprintf("alignment value must be power of 2"));
+        return ira->codegen->builtin_types.entry_invalid;
+    }
 
     AstNode *source_node = instruction->base.source_node;
     if (tld_var->set_global_align_node) {
diff --git a/test/run_tests.cpp b/test/run_tests.cpp
index 987e72aaf9655ceb0b30272fafed9b21c48a3ded..e48c080a54d2cee3379b9de4bcd36e9a0a016f9d 100644
--- a/test/run_tests.cpp
+++ b/test/run_tests.cpp
@@ -1662,6 +1662,13 @@ fn foo() {
 }
     )SOURCE", 1, ".tmp_source.zig:3:24: error: integer value 753664 cannot be implicitly casted to type 'u16'");
 
+    add_compile_fail_case("set global variable alignment to non power of 2", R"SOURCE(
+const some_data: [100]u8 = {
+    @setGlobalAlign(some_data, 3);
+    undefined
+};
+    )SOURCE", 1, ".tmp_source.zig:3:32: error: alignment value must be power of 2");
+
 }
 
 //////////////////////////////////////////////////////////////////////////////