Remove unnecessary local variables to work around an icc optimization bug.

Buildfarm member dunlin has been crashing since commit 8b49a604, but other
machines seem fine with that code.  It turns out that removing the local
variables in ordered_set_startup() that are copies of fields in "qstate"
dodges the problem.  This might cost a few cycles on register-rich
machines, but it's probably a wash on others, and in any case this code
isn't performance-critical.  Thanks to Jeremy Drake for off-list
investigation.

src/backend/utils/adt/orderedsetaggs.c

@@ -159,27 +159,17 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
 		if (use_tuples)
 		{
 			bool		ishypothetical = (aggref->aggkind == AGGKIND_HYPOTHETICAL);
-			AttrNumber *sortColIdx;
-			Oid		   *sortOperators;
-			Oid		   *eqOperators;
-			Oid		   *sortCollations;
-			bool	   *sortNullsFirsts;
 			ListCell   *lc;
 			int			i;
 
 			if (ishypothetical)
 				numSortCols++;	/* make space for flag column */
 			qstate->numSortCols = numSortCols;
-			qstate->sortColIdx = sortColIdx =
-				(AttrNumber *) palloc(numSortCols * sizeof(AttrNumber));
-			qstate->sortOperators = sortOperators =
-				(Oid *) palloc(numSortCols * sizeof(Oid));
-			qstate->eqOperators = eqOperators =
-				(Oid *) palloc(numSortCols * sizeof(Oid));
-			qstate->sortCollations = sortCollations =
-				(Oid *) palloc(numSortCols * sizeof(Oid));
-			qstate->sortNullsFirsts = sortNullsFirsts =
-				(bool *) palloc(numSortCols * sizeof(bool));
+			qstate->sortColIdx = (AttrNumber *) palloc(numSortCols * sizeof(AttrNumber));
+			qstate->sortOperators = (Oid *) palloc(numSortCols * sizeof(Oid));
+			qstate->eqOperators = (Oid *) palloc(numSortCols * sizeof(Oid));
+			qstate->sortCollations = (Oid *) palloc(numSortCols * sizeof(Oid));
+			qstate->sortNullsFirsts = (bool *) palloc(numSortCols * sizeof(bool));
 
 			i = 0;
 			foreach(lc, sortlist)
@@ -191,22 +181,22 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
 				/* the parser should have made sure of this */
 				Assert(OidIsValid(sortcl->sortop));
 
-				sortColIdx[i] = tle->resno;
-				sortOperators[i] = sortcl->sortop;
-				eqOperators[i] = sortcl->eqop;
-				sortCollations[i] = exprCollation((Node *) tle->expr);
-				sortNullsFirsts[i] = sortcl->nulls_first;
+				qstate->sortColIdx[i] = tle->resno;
+				qstate->sortOperators[i] = sortcl->sortop;
+				qstate->eqOperators[i] = sortcl->eqop;
+				qstate->sortCollations[i] = exprCollation((Node *) tle->expr);
+				qstate->sortNullsFirsts[i] = sortcl->nulls_first;
 				i++;
 			}
 
 			if (ishypothetical)
 			{
 				/* Add an integer flag column as the last sort column */
-				sortColIdx[i] = list_length(aggref->args) + 1;
-				sortOperators[i] = Int4LessOperator;
-				eqOperators[i] = Int4EqualOperator;
-				sortCollations[i] = InvalidOid;
-				sortNullsFirsts[i] = false;
+				qstate->sortColIdx[i] = list_length(aggref->args) + 1;
+				qstate->sortOperators[i] = Int4LessOperator;
+				qstate->eqOperators[i] = Int4EqualOperator;
+				qstate->sortCollations[i] = InvalidOid;
+				qstate->sortNullsFirsts[i] = false;
 				i++;
 			}