From a81a9f78fdb1b017c341c54d4602c1dee75c1a23 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Mon, 4 Apr 2022 11:38:49 +0000
Subject: [PATCH] Performance optimization and stronger assert()s in the
 comparison opcodes.

FossilOrigin-Name: e0305e640b9078c7eed9ab0bcc14f4515b54e7cd9ade3306bc2d1660f05b2725
---
 manifest      | 12 ++++++------
 manifest.uuid |  2 +-
 src/vdbe.c    | 19 ++++++++++++-------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/manifest b/manifest
index bf99d99766..225a47a011 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Only\sinvoke\ssqlite3VdbeClearObject()\sfrom\sa\ssingle\slocation,\sso\sthat\sthe\ncompiler\sis\smore\slikely\sto\sin-line\sthe\scode.\s\sPerformance\sincrease\sand\nsize\sreduction.
-D 2022-04-04T01:12:11.426
+C Performance\soptimization\sand\sstronger\sassert()s\sin\sthe\scomparison\sopcodes.
+D 2022-04-04T11:38:49.588
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -624,7 +624,7 @@ F src/upsert.c 8789047a8f0a601ea42fa0256d1ba3190c13746b6ba940fe2d25643a7e991937
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
 F src/util.c 602fe229f32a96ceccae4f40824129669582096f7c355f53dbac156c9fecef23
 F src/vacuum.c 6c38ddc52f0619865c91dae9c441d4d48bf3040d7dc1bc5b22da1e45547ed0b3
-F src/vdbe.c b34327e7ea940885db12df0ae7f751b53106a4eb7047c9a2bfb7efe26e39fc62
+F src/vdbe.c c6e546c9d1ade8e253f54476263d669b2f9af2f57c9de113b1a1096575cfa36e
 F src/vdbe.h 89f5edb1422c8783a0b29db836e409876f2b3e847f78e2b21b1fbcc48a93f85f
 F src/vdbeInt.h 5f3d0abcf30c2b7a6672ad4386f18be0fca9c9b2cefe18f85a2e3df74f2613bf
 F src/vdbeapi.c 354c893f1500cf524cc45c32879b9c68893a28b77e3442c24668d6afe4236217
@@ -1945,8 +1945,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 9564d72a0820dbcb38f905fcd42ed4c858ea8fb5f648b189ceb65380a14a785b
-R dab150b94935a23a5a1bd7213e910e23
+P c6947a96e61f71aa61ca3d70d9e2612d784ab04d60fa88852b03cfce86b1bf2b
+R d512c70bc3a60e0984463bf1a9685f54
 U drh
-Z 70183e42a4b74b2de8511fa6905065a2
+Z 355946a7b8f5d0c9dd9f26b391a9102c
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 22bd606275..e6b956b6cf 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c6947a96e61f71aa61ca3d70d9e2612d784ab04d60fa88852b03cfce86b1bf2b
\ No newline at end of file
+e0305e640b9078c7eed9ab0bcc14f4515b54e7cd9ade3306bc2d1660f05b2725
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index 3f7dd44478..e7343e8207 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -2087,23 +2087,23 @@ case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
     assert( (pOp->p5 & SQLITE_AFF_MASK)!=SQLITE_AFF_TEXT || CORRUPT_DB );
     /* Common case of comparison of two integers */
     if( pIn3->u.i > pIn1->u.i ){
-      iCompare = +1;
       if( sqlite3aGTb[pOp->opcode] ){
         VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
         goto jump_to_p2;
       }
+      iCompare = +1;
     }else if( pIn3->u.i < pIn1->u.i ){
-      iCompare = -1;
       if( sqlite3aLTb[pOp->opcode] ){
         VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
         goto jump_to_p2;
       }
+      iCompare = -1;
     }else{
-      iCompare = 0;
       if( sqlite3aEQb[pOp->opcode] ){
         VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
         goto jump_to_p2;
       }
+      iCompare = 0;
     }
     VdbeBranchTaken(0, (pOp->p5 & SQLITE_NULLEQ)?2:3);
     break;
@@ -2130,11 +2130,11 @@ case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
       ** then the result is always NULL.
       ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
       */
-      iCompare = 1;    /* Operands are not equal */
       VdbeBranchTaken(2,3);
       if( pOp->p5 & SQLITE_JUMPIFNULL ){
         goto jump_to_p2;
       }
+      iCompare = 1;    /* Operands are not equal */
       break;
     }
   }else{
@@ -2240,9 +2240,8 @@ case OP_ElseEq: {       /* same as TK_ESCAPE, jump */
 ** Set the permutation used by the OP_Compare operator in the next
 ** instruction.  The permutation is stored in the P4 operand.
 **
-** The permutation is only valid until the next OP_Compare that has
-** the OPFLAG_PERMUTE bit set in P5. Typically the OP_Permutation should 
-** occur immediately prior to the OP_Compare.
+** The permutation is only valid for the next opcode which must be
+** an OP_Compare that has the OPFLAG_PERMUTE bit set in P5.
 **
 ** The first integer in the P4 integer array is the length of the array
 ** and does not become part of the permutation.
@@ -2274,6 +2273,8 @@ case OP_Permutation: {
 ** The comparison is a sort comparison, so NULLs compare equal,
 ** NULLs are less than numbers, numbers are less than strings,
 ** and strings are less than blobs.
+**
+** This opcode must be immediately followed by an OP_Jump opcode.
 */
 case OP_Compare: {
   int n;
@@ -2332,6 +2333,7 @@ case OP_Compare: {
       break;
     }
   }
+  assert( pOp[1].opcode==OP_Jump );
   break;
 }
 
@@ -2340,8 +2342,11 @@ case OP_Compare: {
 ** Jump to the instruction at address P1, P2, or P3 depending on whether
 ** in the most recent OP_Compare instruction the P1 vector was less than
 ** equal to, or greater than the P2 vector, respectively.
+**
+** This opcode must immediately follow an OP_Compare opcode.
 */
 case OP_Jump: {             /* jump */
+  assert( pOp>aOp && pOp[-1].opcode==OP_Compare );
   if( iCompare<0 ){
     VdbeBranchTaken(0,4); pOp = &aOp[pOp->p1 - 1];
   }else if( iCompare==0 ){