diff --git a/src/arch/aarch64/CodeGen.zig b/src/arch/aarch64/CodeGen.zig
index 2b863fd359..dc64e77f81 100644
--- a/src/arch/aarch64/CodeGen.zig
+++ b/src/arch/aarch64/CodeGen.zig
@@ -786,6 +786,11 @@ fn allocMem(self: *Self, inst: Air.Inst.Index, abi_size: u32, abi_align: u32) !u
 /// Use a pointer instruction as the basis for allocating stack memory.
 fn allocMemPtr(self: *Self, inst: Air.Inst.Index) !u32 {
     const elem_ty = self.air.typeOfIndex(inst).elemType();
+
+    if (!elem_ty.hasRuntimeBits()) {
+        return self.allocMem(inst, @sizeOf(usize), @alignOf(usize));
+    }
+
     const abi_size = math.cast(u32, elem_ty.abiSize(self.target.*)) catch {
         return self.fail("type '{}' too big to fit into stack frame", .{elem_ty});
     };
diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
index f7713a4e69..25dc8d81aa 100644
--- a/src/arch/x86_64/CodeGen.zig
+++ b/src/arch/x86_64/CodeGen.zig
@@ -852,7 +852,7 @@ fn allocMemPtr(self: *Self, inst: Air.Inst.Index) !u32 {
     const elem_ty = ptr_ty.elemType();
 
     if (!elem_ty.hasRuntimeBits()) {
-        return self.allocMem(inst, 8, 8);
+        return self.allocMem(inst, @sizeOf(usize), @alignOf(usize));
     }
 
     const abi_size = math.cast(u32, elem_ty.abiSize(self.target.*)) catch {