[CBP] Pointer frontend changes + groupshared pointer support (#7848)

Resolves #7628
Resolves: #8197

Primary Goals:
1. Add `Access` to pointer
2. AddressSpace::GroupShared support for pointers (SPIR-V)
3. Add `__getAddress()` to replace `&`
* `&` is not updated to `require(cpu)` since slangpy uses `&`. This
means we must: (1) merge PR; (2) replace `&` with `__getAddress()`; (3)
add `require(cpu)` to `&`

Changes:
* Added to `Ptr` the `Access` generic argument & logic (for
`Access::Read`).
* Moved the generic argument `AddressSpace` from `Ptr` to the end of the
type.
* Added pointer casting support between any `Ptr` as long as the
`AddressSpace` is the same
* Disallow globallycoherent T* and coherent T*
* Disallow const T*, T const*, and const T*
* Fixed .natvis display of `ConstantValue` `ValOperandNode`
* Support generic resolution of type-casted integers
* Added `VariablePointer` emitting for spirv + other minor logic needed
for groupshared pointers

Breaking Changes:
* Anyone using the `AddressSpace` of `Ptr` will now have to account for
the `Access` argument
* we disallow various syntax paired with `Ptr` and `T*`

---------

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

1 files changed, 16 insertions, 24 deletions

diff --git a/tests/autodiff/get-offset-ptr.slang b/tests/autodiff/get-offset-ptr.slang
index 517acb54d..e497f1e48 100644
--- a/tests/autodiff/get-offset-ptr.slang
+++ b/tests/autodiff/get-offset-ptr.slang
@@ -1,40 +1,32 @@
-//TEST:SIMPLE(filecheck=CHECK): -target cuda -line-directive-mode none
+//TEST:COMPARE_COMPUTE(filecheck-buffer=CHECK): -cuda -output-using-type
 
-//CHECK: struct s_bwd_prop_function_Intermediates{{[_0-9]+}}
-//CHECK: {
-//CHECK:     MyDiffPtr{{[_0-9]+}} {{[_A-Za-z0-9]+}};
-//CHECK:     MyDiffPtr{{[_0-9]+}} {{[_A-Za-z0-9]+}};
-//CHECK: };
+// This test just ensures that we compile and run the code.
+// It does not check the correctness of the autodiff.
 
 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out, name outputBuffer
 RWStructuredBuffer<float> outputBuffer;
 
 struct MyDiffPtr
 {
-    uint offset;
-    uint d_offset;
-
-    [BackwardDerivative(__bwd_foo)]
-    float foo() 
-    { 
-        return outputBuffer[offset] * outputBuffer[offset];
-    }
-
-    void __bwd_foo(float grad) 
-    {
-        outputBuffer[d_offset] = 2.f * outputBuffer[offset] * grad;
-    }
+    float data1;
+    float data2;
 };
 
 [Differentiable]
-float function(MyDiffPtr *i)
+float function(Ptr<MyDiffPtr, Access::ReadWrite, AddressSpace::GroupShared> i)
 {
-    return i[0].foo() + i[1].foo();
+    return i[0].data1 + i[1].data2;
 }
 
+groupshared MyDiffPtr s[2];
 [numthreads(1, 1, 1), shader("compute")]
-void main(uint3 dispatchThreadID: SV_DispatchThreadID)
+void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
 {
-    MyDiffPtr s[2] = {{0, 2}, {1, 3}};
-    __bwd_diff(function)(&s[0], 1.0f);
+    s = { { 0, 2 }, { 1, 3 } };
+    float result = 1.0f;
+    let pair = __fwd_diff(function)(__getAddress(s[0]));
+    outputBuffer[0] = pair.getPrimal();
+    outputBuffer[1] = pair.getDifferential();
+    // CHECK: 3.0
+    // CHECK-NEXT: 0.0
 }
\ No newline at end of file