diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
index ba6c6dbf30c8..1ec9c9b195e8 100644
--- a/tools/perf/util/expr.y
+++ b/tools/perf/util/expr.y
@@ -3,6 +3,7 @@
 #define YYDEBUG 1
 #include <assert.h>
 #include <math.h>
+#include <stdlib.h>
 #include "util/debug.h"
 #define IN_EXPR_Y 1
 #include "expr.h"
@@ -82,6 +83,39 @@ static struct ids union_expr(struct ids ids1, struct ids ids2)
 	return result;
 }
 
+static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
+			    bool compute_ids)
+{
+	struct ids result;
+
+	if (!compute_ids) {
+		/*
+		 * Compute the event's value from ID. If the ID isn't known then
+		 * it isn't used to compute the formula so set to NAN.
+		 */
+		struct expr_id_data *data;
+
+		result.val = NAN;
+		if (expr__resolve_id(ctx, id, &data) == 0)
+			result.val = expr_id_data__value(data);
+
+		result.ids = NULL;
+		free(id);
+	} else {
+		/*
+		 * Set the value to BOTTOM to show that any value is possible
+		 * when the event is computed. Create a set of just the ID.
+		 */
+		result.val = BOTTOM;
+		result.ids = ids__new();
+		if (!result.ids || ids__insert(result.ids, id)) {
+			pr_err("Error creating IDs for '%s'", id);
+			free(id);
+		}
+	}
+	return result;
+}
+
 /*
  * If we're not computing ids or $1 and $3 are constants, compute the new
  * constant value using OP. Its invariant that there are no ids.  If computing
@@ -167,32 +201,7 @@ expr: NUMBER
 	$$.val = $1;
 	$$.ids = NULL;
 }
-| ID
-{
-	if (!compute_ids) {
-		/*
-		 * Compute the event's value from ID. If the ID isn't known then
-		 * it isn't used to compute the formula so set to NAN.
-		 */
-		struct expr_id_data *data;
-
-		$$.val = NAN;
-		if (expr__resolve_id(ctx, $1, &data) == 0)
-			$$.val = expr_id_data__value(data);
-
-		$$.ids = NULL;
-		free($1);
-	} else {
-		/*
-		 * Set the value to BOTTOM to show that any value is possible
-		 * when the event is computed. Create a set of just the ID.
-		 */
-		$$.val = BOTTOM;
-		$$.ids = ids__new();
-		if (!$$.ids || ids__insert($$.ids, $1))
-			YYABORT;
-	}
-}
+| ID		{ $$ = handle_id(ctx, $1, compute_ids); }
 | expr '|' expr { BINARY_LONG_OP($$, |, $1, $3); }
 | expr '&' expr { BINARY_LONG_OP($$, &, $1, $3); }
 | expr '^' expr { BINARY_LONG_OP($$, ^, $1, $3); }