ac: add 16-bit support to ac_build_bitfield_reverse()

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/amd/common/ac_llvm_build.c

@@ -2181,6 +2181,11 @@ LLVMValueRef ac_build_bitfield_reverse(struct ac_llvm_context *ctx,
 					    (LLVMValueRef []) { src0 }, 1,
 					    AC_FUNC_ATTR_READNONE);
 		break;
+	case 16:
+		result = ac_build_intrinsic(ctx, "llvm.bitreverse.i16", ctx->i16,
+					    (LLVMValueRef []) { src0 }, 1,
+					    AC_FUNC_ATTR_READNONE);
+		break;
 	default:
 		unreachable(!"invalid bitsize");
 		break;