[clang] [llvm] [HLSL] Implement ddx/ddy_coarse intrinsics (PR #164831)

[Alexander Johnston via llvm-commits]

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@@ -148,6 +148,22 @@ template <typename T> constexpr T ldexp_impl(T X, T Exp) {
   return exp2(Exp) * X;
 }
 
+template <typename T> constexpr T ddx_coarse_impl(T value) {
+#if (__has_builtin(__builtin_spirv_ddx_coarse))
+  return __builtin_spirv_ddx_coarse(value);
+#else
+  return __builtin_hlsl_elementwise_ddx_coarse(value);
+#endif
+}
+
+template <typename T> constexpr T ddy_coarse_impl(T value) {
+#if (__has_builtin(__builtin_spirv_ddy_coarse))
+  return __builtin_spirv_ddy_coarse(value);
+#else
+  return __builtin_hlsl_elementwise_ddy_coarse(value);
+#endif
+}
+
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Alexander-Johnston wrote:

Reverted and implemented as an alias instead

https://github.com/llvm/llvm-project/pull/164831