[clang] [llvm] Adding splitdouble HLSL function (PR #109331)

[Farzon Lotfi via cfe-commits]

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@@ -0,0 +1,16 @@
+; RUN: not opt -S -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s 2>&1 | FileCheck %s
+
+; DXIL operation splitdouble doesn't support vector types.
+; CHECK: in function test_vector_double_split
+; CHECK-SAME: splitdouble doesn't support lowering vector types.
+
+define noundef <3 x i32> @test_vector_double_split(<3 x double> noundef %D) local_unnamed_addr {
+entry:
+  %hlsl.splitdouble = tail call { <3 x i32>, <3 x i32> } @llvm.dx.splitdouble.v3i32(<3 x double> %D)
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farzonl wrote:

remove tail:
```suggestion
  %hlsl.splitdouble = call { <3 x i32>, <3 x i32> } @llvm.dx.splitdouble.v3i32(<3 x double> %D)
```

https://github.com/llvm/llvm-project/pull/109331