diff --git a/ci.jsonnet b/ci.jsonnet
index 3b5bb6baedc2..641bc5db7221 100644
--- a/ci.jsonnet
+++ b/ci.jsonnet
@@ -45,7 +45,7 @@ local verify_ci = (import 'ci/ci_common/ci-check.libsonnet').verify_ci;
   assert std.length(std.toString(import 'ci/ci_common/common.jsonnet')) > 0,
   ci_resources:: (import 'ci/ci_common/ci-resources.libsonnet'),
   overlay: graal_common.ci.overlay,
-  specVersion: "3",
+  specVersion: "4",
   builds: [common.add_excludes_guard(b) for b in (
     common.with_components(compiler.builds, ["compiler"]) +
     common.with_components(wasm.builds, ["wasm"]) +
diff --git a/ci/ci_common/bench-common.libsonnet b/ci/ci_common/bench-common.libsonnet
index 36b24b8dd114..9658628144df 100644
--- a/ci/ci_common/bench-common.libsonnet
+++ b/ci/ci_common/bench-common.libsonnet
@@ -120,6 +120,12 @@
     ]
   },
 
+  generate_fork_tags(suite_obj):: if std.objectHasAll(suite_obj, "tags") && std.objectHasAll(suite_obj.tags, "opt_post_merge") then {
+    tags: {opt_post_merge: [tag +"-many-forks" for tag in suite_obj.tags.opt_post_merge]},
+  } else {
+    tags: {}
+  },
+
   generate_fork_builds(suite_obj, subdir='compiler', forks_file_base_name=null)::
     /* based on a benchmark suite definition, generates the many forks version based on the hidden fields
      * 'forks_batches' that specifies the number of batches this job should be split into and the corresponding
@@ -134,13 +140,12 @@
         local batch_str = if suite_obj.forks_batches > 1 then "batch"+i else null,
         "job_prefix":: "bench-forks-" + subdir,
         "job_suffix":: batch_str,
-        tags: if std.objectHasAll(suite_obj, "tags") then [tag +"-many-forks" for tag in suite_obj.tags] else [],
         "timelimit": suite_obj.forks_timelimit,
         local base_name = if forks_file_base_name != null then forks_file_base_name else suite_obj.suite,
         "environment" +: {
           FORK_COUNT_FILE: "${FORK_COUNTS_DIRECTORY}/" + subdir + "/" + base_name + "_forks" + (if batch_str != null then "_"+batch_str else "") + ".json"
         }
-      }
+      } + $.generate_fork_tags(suite_obj)
       for i in std.range(0, suite_obj.forks_batches - 1)]
     else
       [],
diff --git a/ci/common.jsonnet b/ci/common.jsonnet
index 49d2b5e963f7..b0a948700bee 100644
--- a/ci/common.jsonnet
+++ b/ci/common.jsonnet
@@ -329,7 +329,7 @@ local common_json = import "../common.json";
     },
     opt_post_merge: {
       targets+: ["opt-post-merge"],
-      tags+: []
+      tags+: {opt_post_merge +: []},
     },
     daily: {
       targets+: ["daily"],
diff --git a/compiler/ci/ci_common/compiler-common.libsonnet b/compiler/ci/ci_common/compiler-common.libsonnet
index a3578a6ccafc..407c444d03c4 100644
--- a/compiler/ci/ci_common/compiler-common.libsonnet
+++ b/compiler/ci/ci_common/compiler-common.libsonnet
@@ -55,7 +55,7 @@
     local use_libgraal_profile = libgraal_profiling_only(config.compiler.use_libgraal_profile),
 
     job_prefix:: "bench-compiler",
-    tags+: ["bench-compiler"],
+    tags+: {opt_post_merge+: ["bench-compiler"]},
     python_version : "3",
     packages+: common.deps.svm.packages,
     environment+: {