Add offload test for control flow handling

tests/codegen-llvm/gpu_offload/control_flow.rs

diff --git a/tests/codegen-llvm/gpu_offload/control_flow.rs b/tests/codegen-llvm/gpu_offload/control_flow.rs
new file mode 100644
index 0000000..4a213f5
--- /dev/null
+++ b/tests/codegen-llvm/gpu_offload/control_flow.rs
@@ -0,0 +1,37 @@
+//@ compile-flags: -Zoffload=Test -Zunstable-options -C opt-level=3  -Clto=fat
+//@ no-prefer-dynamic
+//@ needs-offload
+
+// This test verifies that the offload intrinsic is correctly lowered even when the caller
+// contains control flow.
+
+#![feature(abi_gpu_kernel)]
+#![feature(rustc_attrs)]
+#![feature(core_intrinsics)]
+#![no_main]
+
+// CHECK: define{{( dso_local)?}} void @main()
+// CHECK-NOT: define
+// CHECK: %EmptyDesc = alloca %struct.__tgt_bin_desc, align 8
+// CHECK-NEXT: %.offload_baseptrs = alloca [1 x ptr], align 8
+// CHECK-NEXT: %.offload_ptrs = alloca [1 x ptr], align 8
+// CHECK-NEXT: %.offload_sizes = alloca [1 x i64], align 8
+// CHECK-NEXT: %kernel_args = alloca %struct.__tgt_kernel_arguments, align 8
+// CHECK: br label %bb3
+// CHECK-NOT define
+// CHECK: bb3
+// CHECK: call void @__tgt_target_data_begin_mapper(ptr nonnull @anon.{{.*}}.1, i64 -1, i32 1, ptr nonnull %.offload_baseptrs, ptr nonnull %.offload_ptrs, ptr nonnull %.offload_sizes, ptr nonnull @.offload_maptypes.foo, ptr null, ptr null)
+// CHECK: %10 = call i32 @__tgt_target_kernel(ptr nonnull @anon.{{.*}}.1, i64 -1, i32 2097152, i32 256, ptr nonnull @.foo.region_id, ptr nonnull %kernel_args)
+// CHECK-NEXT: call void @__tgt_target_data_end_mapper(ptr nonnull @anon.{{.*}}.1, i64 -1, i32 1, ptr nonnull %.offload_baseptrs, ptr nonnull %.offload_ptrs, ptr nonnull %.offload_sizes, ptr nonnull @.offload_maptypes.foo, ptr null, ptr null)
+#[unsafe(no_mangle)]
+unsafe fn main() {
+    let A = [1.0, 1.0, 1.0, 1.0, 1.0, 1.0];
+
+    for i in 0..100 {
+        core::intrinsics::offload::<_, _, ()>(foo, (A.as_ptr() as *const [f32; 6],));
+    }
+}
+
+unsafe extern "C" {
+    pub fn foo(A: *const [f32; 6]) -> ();
+}