perf expr: Accumulate rather than replace in the context counts

JIRA: https://issues.redhat.com/browse/RHEL-78198

upstream
========
commit 3787cda
Author: Ian Rogers <irogers@google.com>
Date: Thu Jul 10 16:51:20 2025 -0700

description
===========
Metrics will fill in the context to have mappings from an event to a
count. When counts are added they replace existing mappings which
generally shouldn't exist with aggregation. Switch to accumulating to
better support cases where perf stat's aggregation isn't used and we
may see a counter more than once.

    Signed-off-by: Ian Rogers <irogers@google.com>
    Link: https://lore.kernel.org/r/20250710235126.1086011-8-irogers@google.com
    Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Signed-off-by: Michael Petlan <mpetlan@redhat.com>

Author: rfmvh

tools/perf/util/expr.c

@@ -166,8 +166,12 @@ int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
 	data_ptr->kind = EXPR_ID_DATA__VALUE;
 
 	ret = hashmap__set(ctx->ids, id, data_ptr, &old_key, &old_data);
-	if (ret)
+	if (ret) {
 		free(data_ptr);
+	} else if (old_data) {
+		data_ptr->val.val += old_data->val.val;
+		data_ptr->val.source_count += old_data->val.source_count;
+	}
 	free(old_key);
 	free(old_data);
 	return ret;