[clang] [llvm] [HLSL] Implement elementwise popcount (PR #108121)

[Farzon Lotfi via cfe-commits]

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@@ -0,0 +1,31 @@
+; RUN: opt -S -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+; Make sure dxil operation function calls for countbits are generated for all integer types.
+
+; Function Attrs: nounwind
+define noundef i16 @test_countbits_short(i16 noundef %a) {
+entry:
+; CHECK:call i16 @dx.op.unary.i16(i32 31, i16 %{{.*}})
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farzonl wrote:

NIT: There is usually a space after `CHECK:`
```suggestion
; CHECK: call i16 @dx.op.unary.i16(i32 31, i16 %{{.*}})
```

https://github.com/llvm/llvm-project/pull/108121