Factor out the code that tries to avoid evaluating subquery operands if the

other operand is NULL into a subroutine, so that it can be more easily reused
by other parts of the code generator.

FossilOrigin-Name: 3c6c71bcea16443b82234414137dfa1b59e2ee8fe5097906c738fc1228fec4e6

diff --git a/manifest b/manifest
index fcdf5f03446b3565c36d28b69b41db1083976e77..e4cf97a0e092c01afa58cfd97524c6d29b60482d 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improve\sthe\sbytecode\sgenerated\sfor\scomparisons\sso\sthat\sif\sone\soperand\sis\na\ssubquery\sand\sthe\sother\soperand\sevaluates\sto\sNULL,\sthe\ssubquery\soperand\nis\snot\seven\scomputed.\s\sThis\sfixes\s5\sof\sthe\s12\sslow\squeries\sdescribed\nin\s[forum:/forumpost/52651713ac|forum\spost\s52651713ac].
-D 2025-06-28T17:59:15.236
+C Factor\sout\sthe\scode\sthat\stries\sto\savoid\sevaluating\ssubquery\soperands\sif\sthe\nother\soperand\sis\sNULL\sinto\sa\ssubroutine,\sso\sthat\sit\scan\sbe\smore\seasily\sreused\nby\sother\sparts\sof\sthe\scode\sgenerator.
+D 2025-06-30T10:30:47.908
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -736,7 +736,7 @@ F src/date.c 9db4d604e699a73e10b8e85a44db074a1f04c0591a77e2abfd77703f50dce1e9
 F src/dbpage.c b3e218f8ed74fcbb7fa805df8ca669a3718d397617b3d8a8aac3307dc315c4d6
 F src/dbstat.c 73362c0df0f40ad5523a6f5501224959d0976757b511299bf892313e79d14f5c
 F src/delete.c 03a77ba20e54f0f42ebd8eddf15411ed6bdb06a2c472ac4b6b336521bf7cea42
-F src/expr.c b46621069e36a2fbc966215691e4775134e2cc6c7a6e9e54b01cbb70b51d57a5
+F src/expr.c f007ab177a9900d10893a58bf6b756e89144df635bab61b25f37a17390f12778
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
 F src/func.c de47a8295503aa130baae5e6d9868ecf4f7c4dbffa65d83ad1f70bdbac0ee2d6
@@ -2208,11 +2208,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 1ad0169b022b280bcaaf94a7fa231591be96b514230ab5c98fbf15cd7df842dd
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 5508b56fd24016c13981ec280ecdd833007c9d8dd595edb295b984c2b487b5c8
-R c5ec83310afc6f17c7231575eaf1e606
-T *branch * optimize-null-values
-T *sym-optimize-null-values *
-T -sym-trunk *
+P f147bc04776ac0056412f69dfc518016c0d5b4e9d964664e3d88f595fb29dbe0
+R 2a36b21b6d3bc1bf7db15e8f66e788a3
 U drh
-Z 4eeee81d77d56831be900c22e39d8eec
+Z 4ecc3e0b30247a36c4e1fea0e6dc5b85
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index 19505125a7dd90356c9538827d997b77a4fd8c83..2be71002589d0c80dc9ccddf4257680d12cbe743 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-f147bc04776ac0056412f69dfc518016c0d5b4e9d964664e3d88f595fb29dbe0
+3c6c71bcea16443b82234414137dfa1b59e2ee8fe5097906c738fc1228fec4e6

diff --git a/src/expr.c b/src/expr.c
index b4461cf5c602f622261f32e437dfa38b22b0056a..de729ea62fe3e26b549c6dc9b82221e64aaafd38 100644 (file)
--- a/src/expr.c
+++ b/src/expr.c
@@ -5830,6 +5830,67 @@ static void exprCodeBetween(
   testcase( xJump==0 );
 }
 
+/*
+** Compute the two operands of a binary operator.
+**
+** If either operand contains a subquery, then the code strives to
+** compute the operand containing the subquery second.  If the other
+** operand evalutes to NULL, then a jump is made.  The address of the
+** IsNull operand that does this jump is returned.  The caller can use
+** this to optimize the computation so as to avoid doing the potentially
+** expensive subquery.
+**
+** If no optimization opportunities exist, return 0.
+*/
+static int exprComputeOperands(
+  Parse *pParse,     /* Parsing context */
+  Expr *pExpr,       /* The comparison expression */
+  int *pR1,          /* OUT: Register holding the left operand */
+  int *pR2,          /* OUT: Register holding the right operand */
+  int *pFree1,       /* OUT: Temp register to free if not zero */
+  int *pFree2        /* OUT: Another temp register to free if not zero */
+){
+  int addrIsNull;
+  int r1, r2;
+  Vdbe *v = pParse->pVdbe;
+
+  assert( v!=0 );
+  /*
+  ** If the left operand contains a (possibly expensive) subquery and the
+  ** right operand does not and the right operation might be NULL,
+  ** then compute the right operand first and do an IsNull jump if the
+  ** right operand evalutes to NULL.
+  */
+  if( ExprHasProperty(pExpr->pLeft, EP_Subquery)
+   && !ExprHasProperty(pExpr->pRight, EP_Subquery)
+   && sqlite3ExprCanBeNull(pExpr->pRight)
+  ){
+    r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, pFree2);
+    addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, r2);  VdbeCoverage(v);
+  }else{
+    addrIsNull = 0;
+  }
+  r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, pFree1);
+  if( addrIsNull==0 ){
+    /*
+    ** If the right operand contains a subquery and the left operand does not
+    ** and the left operand might be NULL, then check the left operand do
+    ** an IsNull check on the left operand before computing the right
+    ** operand.
+    */
+    if( ExprHasProperty(pExpr->pRight, EP_Subquery)
+     && sqlite3ExprCanBeNull(pExpr->pLeft)
+    ){
+      addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, r1);  VdbeCoverage(v);
+    }
+    r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, pFree2);
+  }
+  *pR1 = r1;
+  *pR2 = r2;
+  return addrIsNull;
+}
+
+
 /*
 ** Generate code for a boolean expression such that a jump is made
 ** to the label "dest" if the expression is true but execution
@@ -6076,75 +6137,47 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       break;
     }
     case TK_IS:
-    case TK_ISNOT:
+    case TK_ISNOT: {
       testcase( pExpr->op==TK_IS );
       testcase( pExpr->op==TK_ISNOT );
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
       op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
-      jumpIfNull = SQLITE_NULLEQ;
-      /* no break */ deliberate_fall_through
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, SQLITE_NULLEQ,
+                  ExprHasProperty(pExpr,EP_Commuted));
+      testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+      testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+      break;
+    }
     case TK_LT:
     case TK_LE:
     case TK_GT:
     case TK_GE:
     case TK_NE:
     case TK_EQ: {
-      int r2Done = 0;
-      int addrBypass = 0;
+      int addrIsNull;
       if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
-      testcase( jumpIfNull==0 );
-      /*
-      ** If the left operand is a (possibly expensive) subquery and the
-      ** right operand is not and the right operation might be NULL and
-      ** the operator is not IS or IS NOT, then compute the right operand
-      ** first and skip the computation of the left operand if the right
-      ** operand is NULL.
-      */
-      if( jumpIfNull!=SQLITE_NULLEQ
-       && ExprHasProperty(pExpr->pLeft, EP_Subquery)
-       && !ExprHasProperty(pExpr->pRight, EP_Subquery)
-       && sqlite3ExprCanBeNull(pExpr->pRight)
-      ){
-        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
-        addrBypass = sqlite3VdbeAddOp2(v, OP_IsNull, r2, dest);
-        VdbeCoverageIf(v, jumpIfNull==SQLITE_JUMPIFNULL);
-        VdbeCoverageIf(v, jumpIfNull!=SQLITE_JUMPIFNULL);
-        if( jumpIfNull==SQLITE_JUMPIFNULL ) addrBypass = 0;
-        r2Done = 1;
-      }
-      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
-      if( !r2Done ){
-        /*
-        ** If the right operand is a subquery and the left operand is not
-        ** and the left operand might be NULL and the comparison operator
-        ** is not IS or IS NOT, then check the left operand to see if it is
-        ** NULL and skip the computation of the right operand if it is.
-        */
-        if( jumpIfNull!=SQLITE_NULLEQ
-         && ExprHasProperty(pExpr->pRight, EP_Subquery)
-         && sqlite3ExprCanBeNull(pExpr->pLeft)
-        ){
-          addrBypass = sqlite3VdbeAddOp2(v, OP_IsNull, r1, dest);
-          VdbeCoverageIf(v, jumpIfNull==SQLITE_JUMPIFNULL);
-          VdbeCoverageIf(v, jumpIfNull!=SQLITE_JUMPIFNULL);
-          if( jumpIfNull==SQLITE_JUMPIFNULL ) addrBypass = 0;
-        }
-        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
-      }
+      addrIsNull = exprComputeOperands(pParse, pExpr,
+                                 &r1, &r2, &regFree1, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, dest, jumpIfNull,ExprHasProperty(pExpr,EP_Commuted));
       assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
       assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
       assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
       assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
-      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
-      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
-      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
-      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
-      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
-      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
-      if( addrBypass ) sqlite3VdbeJumpHere(v, addrBypass);
+      if( addrIsNull ){
+        if( jumpIfNull ){
+          sqlite3VdbeChangeP2(v, addrIsNull, dest);
+        }else{
+          sqlite3VdbeJumpHere(v, addrIsNull);
+        }
+      }
       break;
     }
     case TK_ISNULL: