Change the OP_IfNotZero opcode so that it decrements register P1 by 1 rather

than the value in P3, and so that it only decrements if originally positive.
This avoids decrementing the smallest 64-bit signed integer.

FossilOrigin-Name: 165c044686212fbf7182dd560ad1e57eb4cc9838

2 files changed, 7 insertions, 7 deletions

diff --git a/src/select.c b/src/select.c
index 18344b7d4..e5f4c7fcd 100644
--- a/src/select.c
+++ b/src/select.c
@@ -596,7 +596,7 @@ static void pushOntoSorter(
     ** register is initialized with value of LIMIT+OFFSET.)  After the sorter
     ** fills up, delete the least entry in the sorter after each insert.
     ** Thus we never hold more than the LIMIT+OFFSET rows in memory at once */
-    addr = sqlite3VdbeAddOp3(v, OP_IfNotZero, iLimit, 0, 1); VdbeCoverage(v);
+    addr = sqlite3VdbeAddOp1(v, OP_IfNotZero, iLimit); VdbeCoverage(v);
     sqlite3VdbeAddOp1(v, OP_Last, pSort->iECursor);
     if( pSort->bOrderedInnerLoop ){
       r1 = ++pParse->nMem;
diff --git a/src/vdbe.c b/src/vdbe.c
index 6ccd746ef..0935e8763 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -6012,20 +6012,20 @@ case OP_OffsetLimit: {    /* in1, out2, in3 */
   break;
 }
 
-/* Opcode: IfNotZero P1 P2 P3 * *
-** Synopsis: if r[P1]!=0 then r[P1]-=P3, goto P2
+/* Opcode: IfNotZero P1 P2 * * *
+** Synopsis: if r[P1]!=0 then r[P1]--, goto P2
 **
 ** Register P1 must contain an integer.  If the content of register P1 is
-** 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.
+** initially greater than zero, then decrement the value in register P1.
+** If it is non-zero (negative or positive) and then also 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;
+     if( pIn1->u.i>0 ) pIn1->u.i--;
      goto jump_to_p2;
   }
   break;