From: drh <>
Date: Wed, 24 Sep 2025 00:13:28 +0000 (+0000)
Subject: Improved short-circuit evaluation of AND and OR.  All appears to work, but
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9300c4a13cead839de0be4197d2dcfe86ee3468a;p=thirdparty%2Fsqlite.git

Improved short-circuit evaluation of AND and OR.  All appears to work, but
there are still testing and performance issues to be worked out.

FossilOrigin-Name: 0d4447aa61848deecf9170afce031f7b353b91d58474f3f094ce34e46be7f99e
---

diff --git a/manifest b/manifest
index 99b2e1e370..8266659384 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improvements\sto\sshort-circuit\sevaluation\sof\sAND\sand\sOR\soperators.\nThis\sis\sa\spartial\sand\sincomplete\sresponse\sto\n[forum:/forumpost/f5adeb59ff77c056|forum\spost\sf5adeb59ff77c056].
-D 2025-09-23T17:00:53.262
+C Improved\sshort-circuit\sevaluation\sof\sAND\sand\sOR.\s\sAll\sappears\sto\swork,\sbut\nthere\sare\sstill\stesting\sand\sperformance\sissues\sto\sbe\sworked\sout.
+D 2025-09-24T00:13:28.522
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -693,7 +693,7 @@ F src/date.c b6f92001f4b1f73f21774927488661d28f4dac9cd9701ed96486d96b44f5b058
 F src/dbpage.c 081c59d84f187aa0eb48d98faf9578a00bde360f68438d646a86b618653d2479
 F src/dbstat.c 73362c0df0f40ad5523a6f5501224959d0976757b511299bf892313e79d14f5c
 F src/delete.c 03a77ba20e54f0f42ebd8eddf15411ed6bdb06a2c472ac4b6b336521bf7cea42
-F src/expr.c f232f02788453abfec1d580b83c893b3cbc21f025d39b6ff09b98d9645892b2f
+F src/expr.c 4a7954d065441c552a4b6c79703c67096d872a58263804f906f15e111ee122ac
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
 F src/func.c de47a8295503aa130baae5e6d9868ecf4f7c4dbffa65d83ad1f70bdbac0ee2d6
@@ -2175,8 +2175,11 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 1ad0169b022b280bcaaf94a7fa231591be96b514230ab5c98fbf15cd7df842dd
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 136188c161a8a2d5166798fcbd341bd1d3f81da7291011f806d6b2153544832c
-R 059545ebba6f51ae2a79e5b9f333f6cb
+P cea8bf79e18d55a8658e48a967cd0b7970b6f88badb769cfbb1f66ab24fb9ec8
+R bd21c11f0c7e1866fc947e8383f45ff5
+T *branch * short-circuit
+T *sym-short-circuit *
+T -sym-trunk *
 U drh
-Z b177d9578188ffcb6fd2a4da951dd184
+Z e14eb04d760631ac91058b9280e3cbea
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.tags b/manifest.tags
index bec971799f..a5c0300496 100644
--- a/manifest.tags
+++ b/manifest.tags
@@ -1,2 +1,2 @@
-branch trunk
-tag trunk
+branch short-circuit
+tag short-circuit
diff --git a/manifest.uuid b/manifest.uuid
index b84278d469..a4391c17a4 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cea8bf79e18d55a8658e48a967cd0b7970b6f88badb769cfbb1f66ab24fb9ec8
+0d4447aa61848deecf9170afce031f7b353b91d58474f3f094ce34e46be7f99e
diff --git a/src/expr.c b/src/expr.c
index ed16a4a13e..549949b098 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -2440,9 +2440,8 @@ static int exprComputeOperands(
   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.
+    ** and the left operand might be NULL, then do an IsNull check
+    ** check on the left operand before computing the right operand.
     */
     if( ExprHasProperty(pExpr->pRight, EP_Subquery)
      && sqlite3ExprCanBeNull(pExpr->pLeft)
@@ -5099,18 +5098,54 @@ expr_code_doover:
         }
         testcase( regFree1==0 );
         testcase( regFree2==0 );
-    
       }
       break;
     }
     case TK_AND:
     case TK_OR: {
-      Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
+      int addrSkip, skipOp, regSS = 0;
+      Expr *pAlt;
+
+      assert( TK_AND==OP_And );            testcase( op==TK_AND );
+      assert( TK_OR==OP_Or );              testcase( op==TK_OR );
+      pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
       if( pAlt!=pExpr ){
         pExpr = pAlt;
         goto expr_code_doover;
       }
-      /* no break */ deliberate_fall_through
+      skipOp = op==TK_AND ? OP_IfNot : OP_If;
+      if( exprEvalRhsFirst(pExpr) ){
+        r2 = regSS = sqlite3ExprCodeTarget(pParse, pExpr->pRight, target);
+        addrSkip = sqlite3VdbeAddOp1( v, skipOp, r2);
+        VdbeComment((v, "skip left operand"));
+        VdbeCoverage(v); 
+      }else{
+        r2 = 0;
+        addrSkip = 0;
+      }
+      r1 = regSS = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+      if( addrSkip==0 ){
+        if( ExprHasProperty(pExpr->pRight, EP_Subquery) ){
+          addrSkip = sqlite3VdbeAddOp1(v, skipOp, r1);
+          VdbeComment((v, "skip right operand"));
+          VdbeCoverage(v);
+        }
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree1);
+      }
+      sqlite3VdbeAddOp3(v, op, r2, r1, target);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      if( addrSkip==0 ){
+        /* no-op */
+      }else if( regSS==target ){
+        sqlite3VdbeJumpHere(v, addrSkip);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
+        sqlite3VdbeJumpHere(v, addrSkip);
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+        VdbeComment((v, "short-circut value"));
+      }
+      break;
     }
     case TK_PLUS:
     case TK_STAR:
@@ -5123,8 +5158,6 @@ expr_code_doover:
     case TK_RSHIFT:
     case TK_CONCAT: {
       int addrIsNull;
-      assert( TK_AND==OP_And );            testcase( op==TK_AND );
-      assert( TK_OR==OP_Or );              testcase( op==TK_OR );
       assert( TK_PLUS==OP_Add );           testcase( op==TK_PLUS );
       assert( TK_MINUS==OP_Subtract );     testcase( op==TK_MINUS );
       assert( TK_REM==OP_Remainder );      testcase( op==TK_REM );