[clang] [CIR] Upstream TernaryOp for VectorType (PR #142393)

[Henrich Lauko via cfe-commits]

================
@@ -2190,4 +2190,40 @@ def VecShuffleDynamicOp : CIR_Op<"vec.shuffle.dynamic",
   let hasVerifier = 1;
 }
 
+//===----------------------------------------------------------------------===//
+// VecTernaryOp
+//===----------------------------------------------------------------------===//
+
+def VecTernaryOp : CIR_Op<"vec.ternary",
+                   [Pure, AllTypesMatch<["result", "vec1", "vec2"]>]> {
+  let summary = "The `cond ? a : b` ternary operator for vector types";
+  let description = [{
+    The `cir.vec.ternary` operation represents the C/C++ ternary operator,
+    `?:`, for vector types, which does a `select` on individual elements of the
+    vectors. Unlike a regular `?:` operator, there is no short circuiting. All
+    three arguments are always evaluated.  Because there is no short
+    circuiting, there are no regions in this operation, unlike cir.ternary.
+
+    The first argument is a vector of integral type. The second and third
+    arguments are vectors of the same type and have the same number of elements
+    as the first argument.
+
+    The result is a vector of the same type as the second and third arguments.
+    Each element of the result is `(bool)a[n] ? b[n] : c[n]`.
+  }];
+
+  let arguments = (ins
+    IntegerVector:$cond,
+    CIR_VectorType:$vec1,
+    CIR_VectorType:$vec2
----------------
xlauko wrote:

nit: it would be nicer to have `lhs` and `rhs` to mirror AST representation.

https://github.com/llvm/llvm-project/pull/142393