From 2cc96907e4152291e0b6bca78a0bfbc69ddb8839 Mon Sep 17 00:00:00 2001
From: ArielG-NV <159081215+ArielG-NV@users.noreply.github.com>
Date: Fri, 14 Jun 2024 01:29:35 -0400
Subject: Implement for metal `SV_GroupIndex` (#4385)

* Implement for metal `SV_GroupIndex`

 1. If we don't have `sv_GroupThreadId` available we create one using `SV_GroupIndex`s location data.
 2. We emit code emulating `sv_GroupThreadId` from the same logic that CUDA/CPP uses.

* address most review comments

Addressed all but two: [1](https://github.com/shader-slang/slang/pull/4385#discussion_r1639058473) and [2](https://github.com/shader-slang/slang/pull/4385#issuecomment-2166934855)

I want to enable tests and be sure there is no bugs using CI before I redesign the code so I have a working fallback.

* address comment, enable tests

enable now functioning tests due to `SV_GroupIndex` working with metal

* syntax error with groupThreadID search

did `= param` instead of `= i.param`

* add `sv_groupid` for test + test fixes

* disable test that won't work regardless
---
 tests/metal/thread_position_in_threadgroup.slang | 27 ++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 tests/metal/thread_position_in_threadgroup.slang

(limited to 'tests/metal')

diff --git a/tests/metal/thread_position_in_threadgroup.slang b/tests/metal/thread_position_in_threadgroup.slang
new file mode 100644
index 000000000..a20fe2ec7
--- /dev/null
+++ b/tests/metal/thread_position_in_threadgroup.slang
@@ -0,0 +1,27 @@
+//TEST:SIMPLE(filecheck=CHECK): -entry computeMain -stage compute -target metal -D GROUPID
+//TEST:SIMPLE(filecheck=CHECK): -entry computeMain -stage compute -target metal
+
+//CHECK: computeMain
+
+// ensure we compute the SV_GroupIndex from SV_GroupThreadID and `numthreads`
+// CHECK: thread_position_in_threadgroup
+// CHECK-DAG: *{{.*}}2
+
+RWBuffer<uint> dst;
+
+void indirection(uint groupIndex)
+{
+    dst[groupIndex] = groupIndex;
+}
+
+#define THREAD_COUNT 2
+[numthreads(THREAD_COUNT, 1, 1)]
+#ifdef GROUPID
+void computeMain(uint GI : SV_GroupIndex, uint GTID : SV_GroupThreadID)
+#else
+void computeMain(uint GI : SV_GroupIndex)
+#endif
+{
+    dst[GI + THREAD_COUNT] = GI;
+    indirection(GI);
+} 
\ No newline at end of file
-- 
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