[HLSL] Add WaveActiveCountBits as Langugage builtin function for HLSL

One clang builtins are introduced
 uint WaveActiveCountBits( bool bBit ) as Langugage builtin function for HLSL.

The detail for WaveActiveCountBits is at
https://github.com/microsoft/DirectXShaderCompiler/wiki/Wave-Intrinsics#uint-waveactivecountbits-bool-bbit-

This is only clang part change to make WaveActiveCountBits into AST.
llvm intrinsic for WaveActiveCountBits will be add in separate PR.

Reviewed By: Anastasia

Differential Revision: https://reviews.llvm.org/D126857

clang/include/clang/Basic/Builtins.def

@@ -1693,6 +1693,9 @@ BUILTIN(__builtin_os_log_format, "v*v*cC*.", "p:0:nt")
 // CUDA/HIP
 LANGBUILTIN(__builtin_get_device_side_mangled_name, "cC*.", "ncT", CUDA_LANG)
 
+// HLSL
+LANGBUILTIN(WaveActiveCountBits, "Uib", "nc", HLSL_LANG)
+
 // Builtins for XRay
 BUILTIN(__xray_customevent, "vcC*z", "")
 BUILTIN(__xray_typedevent, "vzcC*z", "")

clang/include/clang/Basic/Builtins.h

@@ -42,6 +42,7 @@ enum LanguageID {
   OCL_PIPE = 0x200,          // builtin requires OpenCL pipe.
   OCL_DSE = 0x400,           // builtin requires OpenCL device side enqueue.
   ALL_OCL_LANGUAGES = 0x800, // builtin for OCL languages.
+  HLSL_LANG = 0x1000,        // builtin requires HLSL.
   ALL_LANGUAGES = C_LANG | CXX_LANG | OBJC_LANG, // builtin for all languages.
   ALL_GNU_LANGUAGES = ALL_LANGUAGES | GNU_LANG,  // builtin requires GNU mode.
   ALL_MS_LANGUAGES = ALL_LANGUAGES | MS_LANG     // builtin requires MS mode.

clang/test/SemaHLSL/Wave.hlsl

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1  -x hlsl -triple dxil--shadermodel6.7-library  %s  -verify
+
+// Make sure WaveActiveCountBits is accepted.
+
+// expected-no-diagnostics
+unsigned foo(bool b) {
+    return WaveActiveCountBits(b);
+}