[clang] [llvm] [HLSL][DXIL][SPIRV] Create llvm dot intrinsic and use for HLSL (PR #102872)

[Farzon Lotfi via cfe-commits]

================
@@ -18528,37 +18520,38 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
     Value *Op1 = EmitScalarExpr(E->getArg(1));
     llvm::Type *T0 = Op0->getType();
     llvm::Type *T1 = Op1->getType();
+
+    // If the arguments are scalars, just emit a multiply
     if (!T0->isVectorTy() && !T1->isVectorTy()) {
       if (T0->isFloatingPointTy())
-        return Builder.CreateFMul(Op0, Op1, "dx.dot");
+        return Builder.CreateFMul(Op0, Op1, "dot");
 
       if (T0->isIntegerTy())
-        return Builder.CreateMul(Op0, Op1, "dx.dot");
+        return Builder.CreateMul(Op0, Op1, "dot");
 
-      // Bools should have been promoted
       llvm_unreachable(
           "Scalar dot product is only supported on ints and floats.");
     }
+    // For vectors, validate types and emit the appropriate intrinsic
+
     // A VectorSplat should have happened
     assert(T0->isVectorTy() && T1->isVectorTy() &&
            "Dot product of vector and scalar is not supported.");
 
-    // A vector sext or sitofp should have happened
-    assert(T0->getScalarType() == T1->getScalarType() &&
-           "Dot product of vectors need the same element types.");
-
     auto *VecTy0 = E->getArg(0)->getType()->getAs<VectorType>();
     [[maybe_unused]] auto *VecTy1 =
         E->getArg(1)->getType()->getAs<VectorType>();
-    // A HLSLVectorTruncation should have happend
+
+    assert(VecTy0->getElementType() == VecTy1->getElementType() &&
+           "Dot product of vectors need the same element types.");
+
     assert(VecTy0->getNumElements() == VecTy1->getNumElements() &&
            "Dot product requires vectors to be of the same size.");
 
     return Builder.CreateIntrinsic(
         /*ReturnType=*/T0->getScalarType(),
-        getDotProductIntrinsic(E->getArg(0)->getType(),
-                               VecTy0->getNumElements()),
-        ArrayRef<Value *>{Op0, Op1}, nullptr, "dx.dot");
+        getDotProductIntrinsic(VecTy0->getElementType()),
+        ArrayRef<Value *>{Op0, Op1}, nullptr, "dot");
----------------
farzonl wrote:

`hlsl.dot`

https://github.com/llvm/llvm-project/pull/102872