spirv: forbid merging logical pointers

Under some architecture/operating system combinations it is forbidden
to return a pointer from a merge, as these pointers must point to a
location at compile time. This adds a check for those cases when
returning a pointer from a block merge.

1 files changed, 19 insertions, 0 deletions

diff --git a/test/cases/compile_errors/spirv_merge_logical_pointers.zig b/test/cases/compile_errors/spirv_merge_logical_pointers.zig
new file mode 100644
index 0000000000..ea81ef903c
--- /dev/null
+++ b/test/cases/compile_errors/spirv_merge_logical_pointers.zig
@@ -0,0 +1,19 @@
+export fn a() void {
+    var x: *i32 = undefined;
+    _ = &x;
+    var y: *i32 = undefined;
+    _ = &y;
+    var rt_cond = false;
+    _ = &rt_cond;
+
+    var z = if (rt_cond) x else y;
+    _ = &z;
+}
+
+// error
+// backend=stage2
+// target=spirv64-vulkan
+//
+// :9:13: error: value with non-mergable pointer type '*i32' depends on runtime control flow
+// :9:17: note: runtime control flow here
+// :9:13: note: pointers with address space 'generic' cannot be returned from a branch on target spirv-vulkan by compiler backend stage2_spirv64