[clang] [HLSL] Support packoffset attribute in AST (PR #89836)

[Chris B via cfe-commits]

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@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -triple dxil-unknown-shadermodel6.3-library -S -finclude-default-header  -ast-dump  -x hlsl %s | FileCheck %s
+
+
+// CHECK: HLSLBufferDecl {{.*}} cbuffer A
+cbuffer A
+{
+    // CHECK-NEXT: VarDecl {{.*}} C1 'float4'
+    // CHECK-NEXT: HLSLPackOffsetAttr {{.*}} 0
+    float4 C1 : packoffset(c);
+    // CHECK-NEXT: VarDecl {{.*}} col:11 C2 'float'
+    // CHECK-NEXT: HLSLPackOffsetAttr {{.*}} 4
+    float C2 : packoffset(c1);
+    // CHECK-NEXT: VarDecl {{.*}} col:11 C3 'float'
+    // CHECK-NEXT: HLSLPackOffsetAttr {{.*}} 5
+    float C3 : packoffset(c1.y);
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llvm-beanz wrote:

How about some valid cases for vector and array cbuffer elements?

https://github.com/llvm/llvm-project/pull/89836