Combine adjacent single-register OP_Copy instructions into a single

multi-register OP_Copy, where possible.  Fix the Synopsis comment for
multi-register OP_Copy instructions to show the correct register ranges.

FossilOrigin-Name: 2ae22dc0cbed2feca4baf89d02aaace0331971d6

1 files changed, 11 insertions, 1 deletions

diff --git a/src/expr.c b/src/expr.c
index 81eb00c96..8ee73acb7 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3428,7 +3428,17 @@ int sqlite3ExprCodeExprList(
     }else{
       int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
       if( inReg!=target+i ){
-        sqlite3VdbeAddOp2(pParse->pVdbe, copyOp, inReg, target+i);
+        VdbeOp *pOp;
+        Vdbe *v = pParse->pVdbe;
+        if( copyOp==OP_Copy
+         && (pOp=sqlite3VdbeGetOp(v, -1))->opcode==OP_Copy
+         && pOp->p1+pOp->p3+1==inReg
+         && pOp->p2+pOp->p3+1==target+i
+        ){
+          pOp->p3++;
+        }else{
+          sqlite3VdbeAddOp2(v, copyOp, inReg, target+i);
+        }
       }
     }
   }