fix: separate EQUIVALENCE_CHECK from RUN_EQY to avoid requiring eqy

EQUIVALENCE_CHECK now only controls writing equivalence check files.
The new RUN_EQY variable (default 0) gates actually executing the eqy
tool, so builds don't fail when eqy is not installed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

Author: oharboe

flow/scripts/cts.tcl

@@ -68,7 +68,7 @@ if { !$::env(SKIP_CTS_REPAIR_TIMING) } {
 
   repair_timing_helper
 
-  if { $::env(EQUIVALENCE_CHECK) } {
+  if { $::env(EQUIVALENCE_CHECK) && $::env(RUN_EQY) } {
     run_equivalence_test
   }
   if { $::env(LEC_CHECK) } {

flow/scripts/variables.yaml

@@ -86,8 +86,15 @@ DETAILED_METRICS:
     - grt
 EQUIVALENCE_CHECK:
   description: >
-    Enable running equivalence checks to verify logical correctness of
-    repair_timing.
+    Enable writing equivalence check files to verify logical correctness of
+    repair_timing. Set RUN_EQY to actually run the eqy tool.
+  default: 0
+  stages:
+    - cts
+RUN_EQY:
+  description: >
+    Actually run the eqy equivalence checking tool. Requires EQUIVALENCE_CHECK
+    to be enabled and eqy to be installed.
   default: 0
   stages:
     - cts