[MLIR][LLVMIR] Add support for atan2 intrinsics op (#127970)

This is similar to #127317

Author: FantasqueX

mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td

@@ -173,6 +173,7 @@ def LLVM_TanOp : LLVM_UnaryIntrOpF<"tan">;
 def LLVM_ASinOp : LLVM_UnaryIntrOpF<"asin">;
 def LLVM_ACosOp : LLVM_UnaryIntrOpF<"acos">;
 def LLVM_ATanOp : LLVM_UnaryIntrOpF<"atan">;
+def LLVM_ATan2Op : LLVM_BinarySameArgsIntrOpF<"atan2">;
 
 def LLVM_SinhOp : LLVM_UnaryIntrOpF<"sinh">;
 def LLVM_CoshOp : LLVM_UnaryIntrOpF<"cosh">;

mlir/test/Target/LLVMIR/Import/intrinsic.ll

@@ -139,6 +139,14 @@ define void @inv_trig_test(float %0, <8 x float> %1) {
 
   ret void
 }
+; CHECK-LABEL:  llvm.func @atan2_test
+define void @atan2_test(float %0, float %1, <8 x float> %2, <8 x float> %3) {
+  ; CHECK:  llvm.intr.atan2(%{{.*}}, %{{.*}}) : (f32, f32) -> f32
+  %5 = call float @llvm.atan2.f32(float %0, float %1)
+  ; CHECK:  llvm.intr.atan2(%{{.*}}, %{{.*}}) : (vector<8xf32>, vector<8xf32>) -> vector<8xf32>
+  %6 = call <8 x float> @llvm.atan2.v8f32(<8 x float> %2, <8 x float> %3)
+  ret void
+}
 ; CHECK-LABEL:  llvm.func @hyperbolic_trig_test
 define void @hyperbolic_trig_test(float %0, <8 x float> %1) {
   ; CHECK: llvm.intr.sinh(%{{.*}}) : (f32) -> f32

mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir

@@ -142,6 +142,15 @@ llvm.func @inv_trig_test(%arg0: f32, %arg1: vector<8xf32>) {
   llvm.return
 }
 
+// CHECK-LABEL: @atan2_test
+llvm.func @atan2_test(%arg0: f32, %arg1: f32, %arg2: vector<8xf32>, %arg3: vector<8xf32>) {
+  // CHECK: call float @llvm.atan2.f32
+  "llvm.intr.atan2"(%arg0, %arg1) : (f32, f32) -> f32
+  // CHECK: call <8 x float> @llvm.atan2.v8f32
+  "llvm.intr.atan2"(%arg2, %arg3) : (vector<8xf32>, vector<8xf32>) -> vector<8xf32>
+  llvm.return
+}
+
 // CHECK-LABEL: @hyperbolic_trig_test
 llvm.func @hyperbolic_trig_test(%arg0: f32, %arg1: vector<8xf32>) {
   // CHECK: call float @llvm.sinh.f32