Index: ext/rtree/rtree.c
==================================================================
--- ext/rtree/rtree.c
+++ ext/rtree/rtree.c
@@ -1351,19 +1351,19 @@
 ** to which the constraint applies. The leftmost coordinate column
 ** is 'a', the second from the left 'b' etc.
 */
 static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
   int rc = SQLITE_OK;
-  int ii, cCol;
+  int ii;
 
   int iIdx = 0;
   char zIdxStr[RTREE_MAX_DIMENSIONS*8+1];
   memset(zIdxStr, 0, sizeof(zIdxStr));
   UNUSED_PARAMETER(tab);
 
   assert( pIdxInfo->idxStr==0 );
-  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+  for(ii=0; ii<pIdxInfo->nConstraint && iIdx<(sizeof(zIdxStr)-1); ii++){
     struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
 
     if( p->usable && p->iColumn==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
       /* We have an equality constraint on the rowid. Use strategy 1. */
       int jj;
@@ -1383,13 +1383,11 @@
       pIdxInfo->estimatedCost = 10.0;
       return SQLITE_OK;
     }
 
     if( p->usable && (p->iColumn>0 || p->op==SQLITE_INDEX_CONSTRAINT_MATCH) ){
-      int j, opmsk;
-      static const unsigned char compatible[] = { 0, 0, 1, 1, 2, 2 };
-      u8 op = 0;
+      u8 op;
       switch( p->op ){
         case SQLITE_INDEX_CONSTRAINT_EQ: op = RTREE_EQ; break;
         case SQLITE_INDEX_CONSTRAINT_GT: op = RTREE_GT; break;
         case SQLITE_INDEX_CONSTRAINT_LE: op = RTREE_LE; break;
         case SQLITE_INDEX_CONSTRAINT_LT: op = RTREE_LT; break;
@@ -1397,41 +1395,14 @@
         default:
           assert( p->op==SQLITE_INDEX_CONSTRAINT_MATCH );
           op = RTREE_MATCH; 
           break;
       }
-      assert( op!=0 );
-
-      /* Make sure this particular constraint has not been used before.
-      ** If it has been used before, ignore it.
-      **
-      ** A <= or < can be used if there is a prior >= or >.
-      ** A >= or > can be used if there is a prior < or <=.
-      ** A <= or < is disqualified if there is a prior <=, <, or ==.
-      ** A >= or > is disqualified if there is a prior >=, >, or ==.
-      ** A == is disqualifed if there is any prior constraint.
-      */
-      assert( compatible[RTREE_EQ & 7]==0 );
-      assert( compatible[RTREE_LT & 7]==1 );
-      assert( compatible[RTREE_LE & 7]==1 );
-      assert( compatible[RTREE_GT & 7]==2 );
-      assert( compatible[RTREE_GE & 7]==2 );
-      cCol = p->iColumn - 1 + 'a';
-      opmsk = compatible[op & 7];
-      for(j=0; j<iIdx; j+=2){
-        if( zIdxStr[j+1]==cCol && (compatible[zIdxStr[j] & 7] & opmsk)!=0 ){
-          op = 0;
-          break;
-        }
-      }
-      if( op ){
-        assert( iIdx<sizeof(zIdxStr)-1 );
-        zIdxStr[iIdx++] = op;
-        zIdxStr[iIdx++] = cCol;
-        pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
-        pIdxInfo->aConstraintUsage[ii].omit = 1;
-      }
+      zIdxStr[iIdx++] = op;
+      zIdxStr[iIdx++] = p->iColumn - 1 + 'a';
+      pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
+      pIdxInfo->aConstraintUsage[ii].omit = 1;
     }
   }
 
   pIdxInfo->idxNum = 2;
   pIdxInfo->needToFreeIdxStr = 1;

Index: ext/rtree/rtree6.test
==================================================================
--- ext/rtree/rtree6.test
+++ ext/rtree/rtree6.test
@@ -103,7 +103,41 @@
   SELECT * FROM t1,t2 WHERE k=ii AND x1<v
 } {
   0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 2: (~0 rows)} 
   0 1 1 {SEARCH TABLE t2 USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)}
 }
+
+do_execsql_test rtree6-3.1 {
+  CREATE VIRTUAL TABLE t3 USING rtree(id, x1, x2, y1, y2);
+  INSERT INTO t3 VALUES(NULL, 1, 1, 2, 2);
+  SELECT * FROM t3 WHERE 
+    x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+    x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+    x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+    x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+    x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+    x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5;
+} {1 1.0 1.0 2.0 2.0}
+
+do_test rtree6.3.2 {
+  rtree_strategy {
+    SELECT * FROM t3 WHERE 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 
+  }
+} {EaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEa}
+do_test rtree6.3.4 {
+  rtree_strategy {
+    SELECT * FROM t3 WHERE 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND 
+      x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5 AND x1>0.5
+  }
+} {EaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEaEa}
+
 
 finish_test