Merge the 3.8.12 beta changes from trunk.

FossilOrigin-Name: 35b1b8d4b97715030700e37b292bb4f1bb3f44d6

src/mutex_w32.c

@@ -87,7 +87,10 @@ void sqlite3MemoryBarrier(void){
   SQLITE_MEMORY_BARRIER;
 #elif defined(__GNUC__)
   __sync_synchronize();
-#else
+#elif !defined(SQLITE_DISABLE_INTRINSIC) && \
+      defined(_MSC_VER) && _MSC_VER>=1300
+  _ReadWriteBarrier();
+#elif defined(MemoryBarrier)
   MemoryBarrier();
 #endif
 }

src/pragma.c

@@ -1361,8 +1361,9 @@ void sqlite3Pragma(
     */
     static const int iLn = VDBE_OFFSET_LINENO(2);
     static const VdbeOpList endCode[] = {
-      { OP_IfNeg,       1, 0,        0},    /* 0 */
-      { OP_String8,     0, 3,        0},    /* 1 */
+      { OP_AddImm,      1, 0,        0},    /* 0 */
+      { OP_If,          1, 0,        0},    /* 1 */
+      { OP_String8,     0, 3,        0},    /* 2 */
       { OP_ResultRow,   3, 1,        0},
     };
 
@@ -1563,9 +1564,9 @@ void sqlite3Pragma(
       } 
     }
     addr = sqlite3VdbeAddOpList(v, ArraySize(endCode), endCode, iLn);
-    sqlite3VdbeChangeP3(v, addr, -mxErr);
-    sqlite3VdbeJumpHere(v, addr);
-    sqlite3VdbeChangeP4(v, addr+1, "ok", P4_STATIC);
+    sqlite3VdbeChangeP2(v, addr, -mxErr);
+    sqlite3VdbeJumpHere(v, addr+1);
+    sqlite3VdbeChangeP4(v, addr+2, "ok", P4_STATIC);
   }
   break;
 #endif /* SQLITE_OMIT_INTEGRITY_CHECK */

src/select.c

@@ -579,7 +579,7 @@ static void pushOntoSorter(
     }else{
       iLimit = pSelect->iLimit;
     }
-    addr = sqlite3VdbeAddOp3(v, OP_IfNotZero, iLimit, 0, -1); VdbeCoverage(v);
+    addr = sqlite3VdbeAddOp3(v, OP_IfNotZero, iLimit, 0, 1); VdbeCoverage(v);
     sqlite3VdbeAddOp1(v, OP_Last, pSort->iECursor);
     sqlite3VdbeAddOp1(v, OP_Delete, pSort->iECursor);
     sqlite3VdbeJumpHere(v, addr);
@@ -595,11 +595,8 @@ static void codeOffset(
   int iContinue     /* Jump here to skip the current record */
 ){
   if( iOffset>0 ){
-    int addr;
-    addr = sqlite3VdbeAddOp3(v, OP_IfNeg, iOffset, 0, -1); VdbeCoverage(v);
-    sqlite3VdbeGoto(v, iContinue);
-    VdbeComment((v, "skip OFFSET records"));
-    sqlite3VdbeJumpHere(v, addr);
+    sqlite3VdbeAddOp3(v, OP_IfPos, iOffset, iContinue, 1); VdbeCoverage(v);
+    VdbeComment((v, "OFFSET"));
   }
 }
 
@@ -1815,7 +1812,7 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
   Vdbe *v = 0;
   int iLimit = 0;
   int iOffset;
-  int addr1, n;
+  int n;
   if( p->iLimit ) return;
 
   /* 
@@ -1850,14 +1847,10 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
       sqlite3ExprCode(pParse, p->pOffset, iOffset);
       sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v);
       VdbeComment((v, "OFFSET counter"));
-      addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset); VdbeCoverage(v);
-      sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
-      sqlite3VdbeJumpHere(v, addr1);
+      sqlite3VdbeAddOp3(v, OP_SetIfNotPos, iOffset, iOffset, 0);
       sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
       VdbeComment((v, "LIMIT+OFFSET"));
-      addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit); VdbeCoverage(v);
-      sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
-      sqlite3VdbeJumpHere(v, addr1);
+      sqlite3VdbeAddOp3(v, OP_SetIfNotPos, iLimit, iOffset+1, -1);
     }
   }
 }
@@ -2273,6 +2266,11 @@ static int multiSelect(
       if( p->iLimit ){
         addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v);
         VdbeComment((v, "Jump ahead if LIMIT reached"));
+        if( p->iOffset ){
+          sqlite3VdbeAddOp3(v, OP_SetIfNotPos, p->iOffset, p->iOffset, 0);
+          sqlite3VdbeAddOp3(v, OP_Add, p->iLimit, p->iOffset, p->iOffset+1);
+          sqlite3VdbeAddOp3(v, OP_SetIfNotPos, p->iLimit, p->iOffset+1, -1);
+        }
       }
       explainSetInteger(iSub2, pParse->iNextSelectId);
       rc = sqlite3Select(pParse, p, &dest);

src/sqliteInt.h

@@ -196,6 +196,7 @@
 #      include <intrin.h>
 #      pragma intrinsic(_byteswap_ushort)
 #      pragma intrinsic(_byteswap_ulong)
+#      pragma intrinsic(_ReadWriteBarrier)
 #    else
 #      include <cmnintrin.h>
 #    endif

src/vdbe.c

@@ -5732,12 +5732,12 @@ case OP_MemMax: {        /* in2 */
 }
 #endif /* SQLITE_OMIT_AUTOINCREMENT */
 
-/* Opcode: IfPos P1 P2 * * *
-** Synopsis: if r[P1]>0 goto P2
+/* Opcode: IfPos P1 P2 P3 * *
+** Synopsis: if r[P1]>0 then r[P1]-=P3, goto P2
 **
 ** Register P1 must contain an integer.
-** If the value of register P1 is 1 or greater, jump to P2 and
-** add the literal value P3 to register P1.
+** If the value of register P1 is 1 or greater, subtract P3 from the
+** value in P1 and jump to P2.
 **
 ** If the initial value of register P1 is less than 1, then the
 ** value is unchanged and control passes through to the next instruction.
@@ -5746,38 +5746,44 @@ case OP_IfPos: {        /* jump, in1 */
   pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
   VdbeBranchTaken( pIn1->u.i>0, 2);
-  if( pIn1->u.i>0 ) goto jump_to_p2;
+  if( pIn1->u.i>0 ){
+    pIn1->u.i -= pOp->p3;
+    goto jump_to_p2;
+  }
   break;
 }
 
-/* Opcode: IfNeg P1 P2 P3 * *
-** Synopsis: r[P1]+=P3, if r[P1]<0 goto P2
+/* Opcode: SetIfNotPos P1 P2 P3 * *
+** Synopsis: if r[P1]<=0 then r[P2]=P3
 **
-** Register P1 must contain an integer.  Add literal P3 to the value in
-** register P1 then if the value of register P1 is less than zero, jump to P2. 
+** Register P1 must contain an integer.
+** If the value of register P1 is not positive (if it is less than 1) then
+** set the value of register P2 to be the integer P3.
 */
-case OP_IfNeg: {        /* jump, in1 */
+case OP_SetIfNotPos: {        /* in1, in2 */
   pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
-  pIn1->u.i += pOp->p3;
-  VdbeBranchTaken(pIn1->u.i<0, 2);
-  if( pIn1->u.i<0 ) goto jump_to_p2;
+  if( pIn1->u.i<=0 ){
+    pOut = out2Prerelease(p, pOp);
+    pOut->u.i = pOp->p3;
+  }
   break;
 }
 
 /* Opcode: IfNotZero P1 P2 P3 * *
-** Synopsis: if r[P1]!=0 then r[P1]+=P3, goto P2
+** Synopsis: if r[P1]!=0 then r[P1]-=P3, goto P2
 **
 ** Register P1 must contain an integer.  If the content of register P1 is
-** initially nonzero, then add P3 to P1 and jump to P2.  If register P1 is
-** initially zero, leave it unchanged and fall through.
+** initially nonzero, then subtract P3 from the value in register P1 and
+** jump to P2.  If register P1 is initially zero, leave it unchanged
+** and fall through.
 */
 case OP_IfNotZero: {        /* jump, in1 */
   pIn1 = &aMem[pOp->p1];
   assert( pIn1->flags&MEM_Int );
   VdbeBranchTaken(pIn1->u.i<0, 2);
   if( pIn1->u.i ){
-     pIn1->u.i += pOp->p3;
+     pIn1->u.i -= pOp->p3;
      goto jump_to_p2;
   }
   break;

src/vtab.c

@@ -1145,7 +1145,7 @@ int sqlite3VtabEponymousTableInit(Parse *pParse, Module *pMod){
 */
 void sqlite3VtabEponymousTableClear(sqlite3 *db, Module *pMod){
   Table *pTab = pMod->pEpoTab;
-  if( (pTab = pMod->pEpoTab)!=0 ){
+  if( pTab!=0 ){
     sqlite3DeleteColumnNames(db, pTab);
     sqlite3VtabClear(db, pTab);
     sqlite3DbFree(db, pTab);

src/whereexpr.c

@@ -950,7 +950,6 @@ static void exprAnalyze(
         pNew = pTerm;
       }
       exprCommute(pParse, pDup);
-      pLeft = sqlite3ExprSkipCollate(pDup->pLeft);
       pNew->leftCursor = iCur;
       pNew->u.leftColumn = iColumn;
       testcase( (prereqLeft | extraRight) != prereqLeft );