Suppress variable-set-but-not-used warning from clang 13.

In the normal configuration where GEQO_DEBUG isn't defined,
recent clang versions have started to complain that geqo_main.c
accumulates the edge_failures count but never does anything
with it.  As a minimal back-patchable fix, insert a void cast
to silence this warning.  (I'd speculated about ripping out the
GEQO_DEBUG logic altogether, but I don't think we'd wish to
back-patch that.)

Per recently-established project policy, this is a candidate
for back-patching into out-of-support branches: it suppresses
an annoying compiler warning but changes no behavior.  Hence,
back-patch all the way to 9.2.

Discussion: https://postgr.es/m/CA+hUKGLTSZQwES8VNPmWO9AO0wSeLt36OCPDAZTccT1h7Q7kTQ@mail.gmail.com

diff --git a/src/backend/optimizer/geqo/geqo_main.c b/src/backend/optimizer/geqo/geqo_main.c
index 333a26a695c0f19777e29e78a56ded1837884d89..68ed74325c34d1ab84928ef142265cabeff10ab4 100644 (file)
--- a/src/backend/optimizer/geqo/geqo_main.c
+++ b/src/backend/optimizer/geqo/geqo_main.c
@@ -227,12 +227,17 @@ geqo(PlannerInfo *root, int number_of_rels, List *initial_rels)
    }
 
 
-#if defined(ERX) && defined(GEQO_DEBUG)
+#if defined(ERX)
+#if defined(GEQO_DEBUG)
    if (edge_failures != 0)
        elog(LOG, "[GEQO] failures: %d, average: %d",
             edge_failures, (int) number_generations / edge_failures);
    else
        elog(LOG, "[GEQO] no edge failures detected");
+#else
+   /* suppress variable-set-but-not-used warnings from some compilers */
+   (void) edge_failures;
+#endif
 #endif
 
 #if defined(CX) && defined(GEQO_DEBUG)