[arith] Allow integer casts of 0-D vectors

This just works, no reason to disallow it.

Differential Revision: https://reviews.llvm.org/D142137

Author: d0k

mlir/include/mlir/Dialect/Arith/IR/ArithOps.td

@@ -102,7 +102,7 @@ class Arith_CastOp<string mnemonic, TypeConstraint From, TypeConstraint To,
 // excluding indices: signless integers, vectors or tensors thereof.
 def SignlessFixedWidthIntegerLike : TypeConstraint<Or<[
         AnySignlessInteger.predicate,
-        VectorOf<[AnySignlessInteger]>.predicate,
+        VectorOfAnyRankOf<[AnySignlessInteger]>.predicate,
         TensorOf<[AnySignlessInteger]>.predicate]>,
     "signless-fixed-width-integer-like">;
 

mlir/test/Conversion/ArithToLLVM/arith-to-llvm.mlir

@@ -297,6 +297,18 @@ func.func @integer_extension_and_truncation(%arg0 : i3) {
   return
 }
 
+// CHECK-LABEL: @integer_cast_0d_vector
+func.func @integer_cast_0d_vector(%arg0 : vector<i3>) {
+// CHECK: %[[ARG0:.*]] = builtin.unrealized_conversion_cast
+// CHECK-NEXT: = llvm.sext %[[ARG0]] : vector<1xi3> to vector<1xi6>
+  %0 = arith.extsi %arg0 : vector<i3> to vector<i6>
+// CHECK-NEXT: = llvm.zext %[[ARG0]] : vector<1xi3> to vector<1xi6>
+  %1 = arith.extui %arg0 : vector<i3> to vector<i6>
+// CHECK-NEXT: = llvm.trunc %[[ARG0]] : vector<1xi3> to vector<1xi2>
+  %2 = arith.trunci %arg0 : vector<i3> to vector<i2>
+  return
+}
+
 // CHECK-LABEL: func @fcmp(%arg0: f32, %arg1: f32) {
 func.func @fcmp(f32, f32) -> () {
 ^bb0(%arg0: f32, %arg1: f32):