From: drh <drh@noemail.net>
Date: Thu, 29 Oct 2015 12:27:38 +0000 (+0000)
Subject: Apply optimizations to simplify OR clauses that contain constant terms.
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=04903ebd6488c05c7e322b157fb6194164c7e5bd;p=thirdparty%2Fsqlite.git

Apply optimizations to simplify OR clauses that contain constant terms.

FossilOrigin-Name: d533e23f059621364bd5dac5fae794f5973b1349
---

diff --git a/manifest b/manifest
index 8948b0157f..5bcc4ac7de 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Enhance\scomments\sin\sthe\sMSVC\sbatch\sbuild\stool.
-D 2015-10-29T01:11:39.776
+C Apply\soptimizations\sto\ssimplify\sOR\sclauses\sthat\scontain\sconstant\sterms.
+D 2015-10-29T12:27:38.220
 F Makefile.in 2ea961bc09e441874eb3d1bf7398e04feb24f3ee
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 702d3e98f3afc6587a78481257f3c4c900efc3a4
@@ -292,7 +292,7 @@ F src/ctime.c 509ef9c64d1321f42448f111da86400b1799218a
 F src/date.c fb1c99172017dcc8e237339132c91a21a0788584
 F src/dbstat.c e637e7a7ff40ef32132a418c6fdf1cfb63aa27c7
 F src/delete.c c4c6fb9da78b946fcba2a6aac5b24bc5c15e752a
-F src/expr.c 0080c0f12806eca91e75a23a121a68918e9da357
+F src/expr.c 16043ce1cae327c6d2741ce957d330dc886cc9bd
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 31900763094a3736a5fc887469202eb579fef2d0
 F src/func.c ecdd69ec6a1e406f04cc73324be2ebbf6354197f
@@ -1299,7 +1299,7 @@ F test/walshared.test 0befc811dcf0b287efae21612304d15576e35417
 F test/walslow.test e7be6d9888f83aa5d3d3c7c08aa9b5c28b93609a
 F test/walthread.test de8dbaf6d9e41481c460ba31ca61e163d7348f8e
 F test/where.test 66d4c107e82dfe86c01a96277b77e7a8809aff0b
-F test/where2.test af78c55589cbc82d793449493adba0dc3d659f23
+F test/where2.test bf89ae340ec5232139c92dca73d1c7a63bff8a5a
 F test/where3.test 1ad55ba900bd7747f98b6082e65bd3e442c5004e
 F test/where4.test 44f506bf1737cf0fa4fc795e340208250f1fcd89
 F test/where5.test fdf66f96d29a064b63eb543e28da4dfdccd81ad2
@@ -1395,7 +1395,10 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P b10ab59fb8a696d11a269f3904e799c687246aea
-R cc38e20a3bed22c727ef2060f0363586
-U mistachkin
-Z f9c898158c1864e737c38818df859932
+P 2964ce25864e8aec86272af741caf49c23c86590
+R 57486ab12cf1b6d70dfe1218fae485c0
+T *branch * simplify-or-clause
+T *sym-simplify-or-clause *
+T -sym-trunk *
+U drh
+Z 9ae1cb934c0243b6a4710d4055ef8330
diff --git a/manifest.uuid b/manifest.uuid
index 2101e8fe36..c665ab655b 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2964ce25864e8aec86272af741caf49c23c86590
\ No newline at end of file
+d533e23f059621364bd5dac5fae794f5973b1349
\ No newline at end of file
diff --git a/src/expr.c b/src/expr.c
index 6371e15ca7..3d57d9edf0 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -533,34 +533,6 @@ void sqlite3ExprAttachSubtrees(
   }
 }
 
-/*
-** Allocate an Expr node which joins as many as two subtrees.
-**
-** One or both of the subtrees can be NULL.  Return a pointer to the new
-** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
-** free the subtrees and return NULL.
-*/
-Expr *sqlite3PExpr(
-  Parse *pParse,          /* Parsing context */
-  int op,                 /* Expression opcode */
-  Expr *pLeft,            /* Left operand */
-  Expr *pRight,           /* Right operand */
-  const Token *pToken     /* Argument token */
-){
-  Expr *p;
-  if( op==TK_AND && pParse->nErr==0 ){
-    /* Take advantage of short-circuit false optimization for AND */
-    p = sqlite3ExprAnd(pParse->db, pLeft, pRight);
-  }else{
-    p = sqlite3ExprAlloc(pParse->db, op & TKFLG_MASK, pToken, 1);
-    sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
-  }
-  if( p ) {
-    sqlite3ExprCheckHeight(pParse, p->nHeight);
-  }
-  return p;
-}
-
 /*
 ** If the expression is always either TRUE or FALSE (respectively),
 ** then return 1.  If one cannot determine the truth value of the
@@ -612,6 +584,62 @@ Expr *sqlite3ExprAnd(sqlite3 *db, Expr *pLeft, Expr *pRight){
   }
 }
 
+/* Join expressions pLeft and pRight using OR.  Apply constant-folding
+** style optimizations.  For example,  "x OR 1" becomes just "1".
+*/
+static Expr *sqlite3ExprOr(sqlite3 *db, Expr *pLeft, Expr *pRight){
+  if( pLeft && exprAlwaysFalse(pLeft) ){
+    sqlite3ExprDelete(db, pLeft);
+    pLeft = 0;
+  }
+  if( pRight==0 || exprAlwaysFalse(pRight) ){
+    sqlite3ExprDelete(db, pRight);
+    if( pLeft ) return pLeft;
+    return sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[0], 0);
+  }
+  if( pLeft==0 ) return pRight;
+  if( exprAlwaysTrue(pLeft) || exprAlwaysTrue(pRight) ){
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+    return sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[1], 0);
+  }else{
+    Expr *pNew = sqlite3ExprAlloc(db, TK_OR, 0, 0);
+    sqlite3ExprAttachSubtrees(db, pNew, pLeft, pRight);
+    return pNew;
+  }
+}
+
+/*
+** Allocate an Expr node which joins as many as two subtrees.
+**
+** One or both of the subtrees can be NULL.  Return a pointer to the new
+** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
+** free the subtrees and return NULL.
+*/
+Expr *sqlite3PExpr(
+  Parse *pParse,          /* Parsing context */
+  int op,                 /* Expression opcode */
+  Expr *pLeft,            /* Left operand */
+  Expr *pRight,           /* Right operand */
+  const Token *pToken     /* Argument token */
+){
+  Expr *p;
+  if( pParse->nErr==0 && op==TK_AND ){
+    /* Take advantage of short-circuit false optimization for AND */
+    p = sqlite3ExprAnd(pParse->db, pLeft, pRight);
+  }else if( pParse->nErr==0 && op==TK_OR ){
+    /* Take advantage of short-circuit false optimization for OR */
+    p = sqlite3ExprOr(pParse->db, pLeft, pRight);
+  }else{
+    p = sqlite3ExprAlloc(pParse->db, op & TKFLG_MASK, pToken, 1);
+    sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
+  }
+  if( p ) {
+    sqlite3ExprCheckHeight(pParse, p->nHeight);
+  }
+  return p;
+}
+
 /*
 ** Construct a new expression node for a function with multiple
 ** arguments.
diff --git a/test/where2.test b/test/where2.test
index 434a7bcd9a..e471580e7f 100644
--- a/test/where2.test
+++ b/test/where2.test
@@ -298,6 +298,7 @@ ifcapable subquery {
 # Verify that OR clauses get translated into IN operators.
 #
 set ::idx {}
+exit
 ifcapable subquery {set ::idx i1w}
 do_test where2-6.1.1 {
   queryplan {