Change the expression code generator to account for the fact that the new

sqlite3AtoF() never returns NaN.  Also, clarification of a comment in
where.c.

FossilOrigin-Name: 75f596a04a74eb3a538c7be5b41756c970a21a1b

2 files changed, 7 insertions, 8 deletions

diff --git a/src/expr.c b/src/expr.c
index 60787faa2..0ff234ee9 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1708,13 +1708,10 @@ static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
     double value;
     char *zV;
     sqlite3AtoF(z, &value);
-    if( sqlite3IsNaN(value) ){
-      sqlite3VdbeAddOp2(v, OP_Null, 0, iMem);
-    }else{
-      if( negateFlag ) value = -value;
-      zV = dup8bytes(v, (char*)&value);
-      sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
-    }
+    assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
+    if( negateFlag ) value = -value;
+    zV = dup8bytes(v, (char*)&value);
+    sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
   }
 }
 
diff --git a/src/where.c b/src/where.c
index 7d8f05de3..836324156 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3558,7 +3558,9 @@ WhereInfo *sqlite3WhereBegin(
     ** FROM clause entry that permits the lowest-cost, "optimal" scan. In
     ** this context an optimal scan is one that uses the same strategy
     ** for the given FROM clause entry as would be selected if the entry
-    ** were used as the innermost nested loop.
+    ** were used as the innermost nested loop.  In other words, a table
+    ** is chosen such that the cost of running that table cannot be reduced
+    ** by waiting for other tables to run first.
     **
     ** The second iteration is only performed if no optimal scan strategies
     ** were found by the first. This iteration is used to search for the