Enhancements to sqlite3ExprImpliesExpr() so that it realizes that

"iif(A,B)" implies "A".

FossilOrigin-Name: d96ecbee59b50eca25447456dfff2c168e8eade7a68e542932d5829f97debb31

diff --git a/manifest b/manifest
index 2c47dca7a742c4cb6c0393387957ff6e10a78bb9..a34db27f4e39f0f5287c816919e6c98db2b9aedc 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\san\sinaccuracy\sin\sthe\sdocumentation\sin\sfts5.h.
-D 2024-11-27T18:01:25.186
+C Enhancements\sto\ssqlite3ExprImpliesExpr()\sso\sthat\sit\srealizes\sthat\n"iif(A,B)"\simplies\s"A".
+D 2024-11-28T00:34:20.169
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md e108e1e69ae8e8a59e93c455654b8ac9356a11720d3345df2a4743e9590fb20d
@@ -726,7 +726,7 @@ F src/date.c 89ce1ff20512a7fa5070ba6e7dd5c171148ca7d580955795bf97c79c2456144a
 F src/dbpage.c db1be8adaf1f839ad733c08baeac5c22aa912f7b535865c0c061382602081360
 F src/dbstat.c 73362c0df0f40ad5523a6f5501224959d0976757b511299bf892313e79d14f5c
 F src/delete.c 03a77ba20e54f0f42ebd8eddf15411ed6bdb06a2c472ac4b6b336521bf7cea42
-F src/expr.c a9d9f5fdfbdd3b2c94d7af1b11f181464b8a641736cf32cb92fa3c5e7ecb30df
+F src/expr.c bc1e0266dfd88c996e509550220b74b46c7654b0818909adba8ba8227452cd3e
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
 F src/func.c 49489dcce46d2d491cedb451e974264150c473e5f5bba448498a9aa4c1993537
@@ -860,7 +860,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 8b7e309a8012659ac9275ad8cdcc6acaf73fa04b1090e38a01335f230fd10681
 F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
 F src/walker.c d5006d6b005e4ea7302ad390957a8d41ed83faa177e412f89bc5600a7462a014
-F src/where.c 504d72098437ab97dfd3a71cea85e554381650f9dffde277c66603f3e34daddc
+F src/where.c b34adb09fdb2a4f57a0bafd4194b501047ef383976fef9f0ac3f395f4881694d
 F src/whereInt.h 1e36ec50392f7cc3d93d1152d4338064cd522b87156a0739388b7e273735f0ca
 F src/wherecode.c 0c3d3199a2b769a5e2bb70feb5003dc85b3d86842ecaf903a47f2b4205ca5dab
 F src/whereexpr.c 0f93a29cabd3a338d09a1f5c6770620a1ac51ec1157f3229502a7e7767c60b6f
@@ -2201,8 +2201,11 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 1e405c39a8405e2081ce061559d1aacc70055fc74ab86d886b973076a3fb124b
-R 306a37bedf7a72c95bbfd16141af1dca
-U dan
-Z 0f8994542e0c6b090d32b7bcc99e7877
+P ec3ca6f17972a9624018ae352e5a4be8dc34602a4569c80e827e09cd7fbed7f7
+R 7e7059a06e37f0bd3101b74065b6331a
+T *branch * expr-implies-expr
+T *sym-expr-implies-expr *
+T -sym-trunk *
+U drh
+Z 9da80189eab742fa7806914a5f17a037
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index 2abc82dd8354bcbb67cf81f5f76a5eda05a0b84f..f8884a526de8f0c1a642dbefaa6fdbdd0c5a2123 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ec3ca6f17972a9624018ae352e5a4be8dc34602a4569c80e827e09cd7fbed7f7
+d96ecbee59b50eca25447456dfff2c168e8eade7a68e542932d5829f97debb31

diff --git a/src/expr.c b/src/expr.c
index cc915987ddb30dd90da79950f161416400d0e8ad..68cb60012dc9ac5012c0e1818ace7b2c7b2e879b 100644 (file)
--- a/src/expr.c
+++ b/src/expr.c
@@ -6180,16 +6180,20 @@ void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
 ** same as that currently bound to variable pVar, non-zero is returned.
 ** Otherwise, if the values are not the same or if pExpr is not a simple
 ** SQL value, zero is returned.
+**
+** If the SQLITE_EnableQPSG flag is set on the database connection, then
+** this routine always returns false.
 */
-static int exprCompareVariable(
+static SQLITE_NOINLINE int exprCompareVariable(
   const Parse *pParse,
   const Expr *pVar,
   const Expr *pExpr
 ){
-  int res = 0;
+  int res = 2;
   int iVar;
   sqlite3_value *pL, *pR = 0;
  
+  if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) return 2;
   sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB, &pR);
   if( pR ){
     iVar = pVar->iColumn;
@@ -6199,12 +6203,11 @@ static int exprCompareVariable(
       if( sqlite3_value_type(pL)==SQLITE_TEXT ){
         sqlite3_value_text(pL); /* Make sure the encoding is UTF-8 */
       }
-      res =  0==sqlite3MemCompare(pL, pR, 0);
+      res = sqlite3MemCompare(pL, pR, 0) ? 2 : 0;
     }
     sqlite3ValueFree(pR);
     sqlite3ValueFree(pL);
   }
-
   return res;
 }
 
@@ -6230,12 +6233,10 @@ static int exprCompareVariable(
 ** just might result in some slightly slower code.  But returning
 ** an incorrect 0 or 1 could lead to a malfunction.
 **
-** If pParse is not NULL then TK_VARIABLE terms in pA with bindings in
-** pParse->pReprepare can be matched against literals in pB.  The
-** pParse->pVdbe->expmask bitmask is updated for each variable referenced.
-** If pParse is NULL (the normal case) then any TK_VARIABLE term in
-** Argument pParse should normally be NULL. If it is not NULL and pA or
-** pB causes a return value of 2.
+** If pParse is not NULL and SQLITE_EnableQPSG is off then TK_VARIABLE
+** terms in pA with bindings in pParse->pReprepare can be matched against
+** literals in pB.  The pParse->pVdbe->expmask bitmask is updated for
+** each variable referenced.
 */
 int sqlite3ExprCompare(
   const Parse *pParse,
@@ -6247,8 +6248,8 @@ int sqlite3ExprCompare(
   if( pA==0 || pB==0 ){
     return pB==pA ? 0 : 2;
   }
-  if( pParse && pA->op==TK_VARIABLE && exprCompareVariable(pParse, pA, pB) ){
-    return 0;
+  if( pParse && pA->op==TK_VARIABLE ){
+    return exprCompareVariable(pParse, pA, pB);
   }
   combinedFlags = pA->flags | pB->flags;
   if( combinedFlags & EP_IntValue ){
@@ -6443,18 +6444,66 @@ static int exprImpliesNotNull(
   return 0;
 }
 
+/*
+** Return true if the boolean value of the expression is always either
+** FALSE or NULL.
+*/
+static int sqlite3ExprIsNotTrue(Expr *pExpr){
+  int v;
+  if( pExpr->op==TK_NULL ) return 1;
+  if( pExpr->op==TK_TRUEFALSE && sqlite3ExprTruthValue(pExpr)==0 ) return 1;
+  v = 1;
+  if( sqlite3ExprIsInteger(pExpr, &v, 0) && v==0 ) return 1;
+  return 0;
+}
+
+/*
+** Return true if the expression is one of the following:
+**
+**    CASE WHEN x THEN y END
+**    CASE WHEN x THEN y ELSE NULL END
+**    CASE WHEN x THEN y ELSE false END
+**    iif(x,y)
+**    iif(x,y,NULL)
+**    iif(x,y,false)
+*/
+static int sqlite3ExprIsIIF(sqlite3 *db, const Expr *pExpr){
+  ExprList *pList;
+  if( pExpr->op==TK_FUNCTION ){
+    const char *z = pExpr->u.zToken;
+    FuncDef *pDef;
+    if( (z[0]!='i' && z[0]!='I') ) return 0;
+    if( pExpr->x.pList==0 ) return 0;
+    pDef = sqlite3FindFunction(db, z, pExpr->x.pList->nExpr, ENC(db), 0);
+    if( pDef==0 ) return 0;
+    if( (pDef->funcFlags & SQLITE_FUNC_INLINE)==0 ) return 0;
+    if( SQLITE_PTR_TO_INT(pDef->pUserData)!=INLINEFUNC_iif ) return 0;
+  }else if( pExpr->op==TK_CASE ){
+    if( pExpr->pLeft!=0 ) return 0;
+  }else{
+    return 0;
+  }
+  pList = pExpr->x.pList;
+  assert( pList!=0 );
+  if( pList->nExpr==2 ) return 1;
+  if( pList->nExpr==3 && sqlite3ExprIsNotTrue(pList->a[2].pExpr) ) return 1;
+  return 0;
+}
+
 /*
 ** Return true if we can prove the pE2 will always be true if pE1 is
 ** true.  Return false if we cannot complete the proof or if pE2 might
 ** be false.  Examples:
 **
-**     pE1: x==5       pE2: x==5             Result: true
-**     pE1: x>0        pE2: x==5             Result: false
-**     pE1: x=21       pE2: x=21 OR y=43     Result: true
-**     pE1: x!=123     pE2: x IS NOT NULL    Result: true
-**     pE1: x!=?1      pE2: x IS NOT NULL    Result: true
-**     pE1: x IS NULL  pE2: x IS NOT NULL    Result: false
-**     pE1: x IS ?2    pE2: x IS NOT NULL    Result: false
+**     pE1: x==5        pE2: x==5             Result: true
+**     pE1: x>0         pE2: x==5             Result: false
+**     pE1: x=21        pE2: x=21 OR y=43     Result: true
+**     pE1: x!=123      pE2: x IS NOT NULL    Result: true
+**     pE1: x!=?1       pE2: x IS NOT NULL    Result: true
+**     pE1: x IS NULL   pE2: x IS NOT NULL    Result: false
+**     pE1: x IS ?2     pE2: x IS NOT NULL    Result: false
+**     pE1: iif(x,y)    pE2: x                Result: true
+**     PE1: iif(x,y,0)  pE2: x                Result: true
 **
 ** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
 ** Expr.iTable<0 then assume a table number given by iTab.
@@ -6488,6 +6537,9 @@ int sqlite3ExprImpliesExpr(
   ){
     return 1;
   }
+  if( sqlite3ExprIsIIF(pParse->db, pE1) ){
+    return sqlite3ExprImpliesExpr(pParse,pE1->x.pList->a[0].pExpr,pE2,iTab);
+  }
   return 0;
 }
 

diff --git a/src/where.c b/src/where.c
index 1315a8cc37e0165e876fd07dd2db0674ea3ec292..5abb40eced6ef44245dae5f5efce47685aba95bb 100644 (file)
--- a/src/where.c
+++ b/src/where.c
@@ -3564,7 +3564,6 @@ static int whereUsablePartialIndex(
     if( !whereUsablePartialIndex(iTab,jointype,pWC,pWhere->pLeft) ) return 0;
     pWhere = pWhere->pRight;
   }
-  if( pParse->db->flags & SQLITE_EnableQPSG ) pParse = 0;
   for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
     Expr *pExpr;
     pExpr = pTerm->pExpr;