[mlir][spirv] Enable validation of global vars tests (#164974)

Currently the target test will fail with:

```
error: line 12: Initializer type must match the data type
  %var2 = OpVariable %_ptr_Uniform_float Uniform %var1
```

When passed:

```mlir
spirv.module Logical GLSL450 requires #spirv.vce<v1.0, [Shader], []> {
  spirv.GlobalVariable @var1 : !spirv.ptr<f32, Uniform>
  spirv.GlobalVariable @var2 initializer(@var1) bind(1, 0) : !spirv.ptr<f32, Uniform>
}
```

The problem is that we try to initialize `f32` pointer with `f32`
pointer, but the validator fails because it expects `var1` to be `f32`,
not a pointer to `f32`. `spirv.GlobalVariable` only allows pointer type,
so in the current design we cannot initialize one `spirv.GlobalVariable`
with another.

So, for now we disallow initialization of one global variable with
another. In the future we may want to re-work global variables if we
want to support that.

0 files changed, 0 insertions, 0 deletions