[clang] [HLSL] Implement SV_GroupID semantic (PR #115911)

[Zhengxing li via cfe-commits]

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@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -x hlsl -emit-llvm -finclude-default-header -disable-llvm-passes -o - %s | FileCheck %s
+
+// Make sure SV_GroupID translated into dx.group.id.
+
+// CHECK:  define void @foo()
+// CHECK:  %[[#ID:]] = call i32 @llvm.dx.group.id(i32 0)
+// CHECK:  call void @{{.*}}foo{{.*}}(i32 %[[#ID]])
+[shader("compute")]
+[numthreads(8,8,1)]
+void foo(uint Idx : SV_GroupID) {}
+
+// CHECK:  define void @bar()
+// CHECK:  %[[#ID_X:]] = call i32 @llvm.dx.group.id(i32 0)
+// CHECK:  %[[#ID_X_:]] = insertelement <2 x i32> poison, i32 %[[#ID_X]], i64 0
+// CHECK:  %[[#ID_Y:]] = call i32 @llvm.dx.group.id(i32 1)
+// CHECK:  %[[#ID_XY:]] = insertelement <2 x i32> %[[#ID_X_]], i32 %[[#ID_Y]], i64 1
+// CHECK:  call void @{{.*}}bar{{.*}}(<2 x i32> %[[#ID_XY]])
+[shader("compute")]
+[numthreads(8,8,1)]
+void bar(uint2 Idx : SV_GroupID) {}
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lizhengxing wrote:

This test is from `DispatchThreadID.hlsl` .  I'll add the uint3 test in the next commit with the changes from all feedbacks. 

https://github.com/llvm/llvm-project/pull/115911