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

tglsfdc · tglsfdc · commit f90b9998b1e3 · 2022-01-23T11:09:53.000-05:00
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
@@ -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)
