[clang] [llvm] Add normalize builtins and normalize HLSL function to DirectX and SPIR-V backend (PR #102683)

[Farzon Lotfi via cfe-commits]

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@@ -18584,6 +18584,29 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
         CGM.getHLSLRuntime().getLengthIntrinsic(), ArrayRef<Value *>{X},
         nullptr, "hlsl.length");
   }
+  case Builtin::BI__builtin_hlsl_normalize: {
+    Value *X = EmitScalarExpr(E->getArg(0));
+
+    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
+           "normalize operand must have a float representation");
+
+    // scalar inputs should expect a scalar return type
+    if (!E->getArg(0)->getType()->isVectorType())
+      return Builder.CreateIntrinsic(
+          /*ReturnType=*/X->getType()->getScalarType(),
+          CGM.getHLSLRuntime().getNormalizeIntrinsic(), ArrayRef<Value *>{X},
+          nullptr, "hlsl.normalize");
+
+    // construct a vector return type for vector inputs
+    auto *XVecTy = E->getArg(0)->getType()->getAs<VectorType>();
+    llvm::Type *retType = X->getType()->getScalarType();
+    retType = llvm::VectorType::get(
+        retType, ElementCount::getFixed(XVecTy->getNumElements()));
+
+    return Builder.CreateIntrinsic(
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farzonl wrote:

I don't understand why we are checking for  scalars\not scalars and then  emiting the same intrinsic. seems like afree all the asserts\validity checks we should simplify this whole case statement to one `Builder.CreateIntrinsic`

https://github.com/llvm/llvm-project/pull/102683