From: drh <drh@noemail.net>
Date: Thu, 30 May 2019 00:46:37 +0000 (+0000)
Subject: Smaller and faster sqlite3IsNaN() implementation makes deserialization of
X-Git-Tag: version-3.29.0~58
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=05921223c25ae385a5e17bbf5484f5885bb78f2c;p=thirdparty%2Fsqlite.git

Smaller and faster sqlite3IsNaN() implementation makes deserialization of
floating point values much faster.

FossilOrigin-Name: ea748edecb261f2b862d542daff6e99a6fd8879a8ace94b440d99e110577d1c1
---

diff --git a/manifest b/manifest
index 78f25db778..a2a87ce139 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Much\sfaster\simplementation\sof\sapplyNumericAffinity()\sby\savoiding\ssome\nunnecessary\scalls\sto\ssqlite3Atoi64().
-D 2019-05-29T21:18:27.160
+C Smaller\sand\sfaster\ssqlite3IsNaN()\simplementation\smakes\sdeserialization\sof\nfloating\spoint\svalues\smuch\sfaster.
+D 2019-05-30T00:46:37.512
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -527,7 +527,7 @@ F src/shell.c.in 6c992809abf20dbb4aad89299d7c15c98ddf2504b23c83ef71eb435ad392cdc
 F src/sqlite.h.in d19c873a17c2effd4417f687fad942b6cc0ab0c64535f669cc2f22a5b05db23b
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 9ecc93b8493bd20c0c07d52e2ac0ed8bab9b549c7f7955b59869597b650dd8b5
-F src/sqliteInt.h 0769cc94ac573aea0cc293b4f4e12d9cc1fb7549cece32ff6ff781214ced474c
+F src/sqliteInt.h 73d93952552a7a5fdb29ae19ef9919041364070615ba04c2d673126185f523bf
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -592,13 +592,13 @@ F src/trigger.c bb034c08eca111e66a19cda045903a12547c1be2294b5570d794b869d9c44a73
 F src/update.c 3cb9150d2cf661d938e2f1b1749945f3faa767f88febdb739ab1793bbf895ff2
 F src/upsert.c 0dd81b40206841814d46942a7337786932475f085716042d0cb2fc7791bf8ca4
 F src/utf.c 2f0fac345c7660d5c5bd3df9e9d8d33d4c27f366bcfb09e07443064d751a0507
-F src/util.c e278abeb8c82fc84dac998f2f2cf16ef7740333cae9335ce270b9af75e0505a0
+F src/util.c 8d95c976b33953a039d4ebd543c7acc2c9fd03d1cecb3d41ba7fcc0f24fcbe2d
 F src/vacuum.c 82dcec9e7b1afa980288718ad11bc499651c722d7b9f32933c4d694d91cb6ebf
 F src/vdbe.c e6fb674eda4aa32c50d53eb09210c9ed802866cb4d1dc0d6187301b55e4a82b7
 F src/vdbe.h 712bca562eaed1c25506b9faf9680bdc75fc42e2f4a1cd518d883fa79c7a4237
 F src/vdbeInt.h 3ba14553508d66f58753952d6dd287dce4ec735de02c6440858b4891aed51c17
 F src/vdbeapi.c f9161e5c77f512fbb80091ce8af621d19c9556bda5e734cffaac1198407400da
-F src/vdbeaux.c afe8d7858ad7a7cd67b16d0df396f5c672309722c7855d33cd10adb7ce076b4b
+F src/vdbeaux.c 3a803d75875031309204df90977059b12ffb706d16b4baa5e2d99f4353962582
 F src/vdbeblob.c f5c70f973ea3a9e915d1693278a5f890dc78594300cf4d54e64f2b0917c94191
 F src/vdbemem.c 5ecfa992b496c8e46227f1ff2ebae30c7b7a6bc098229c89a8ff49cf27249d69
 F src/vdbesort.c 66592d478dbb46f19aed0b42222325eadb84deb40a90eebe25c6e7c1d8468f47
@@ -1829,7 +1829,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P f9e85e6c79162081f8f512d22951931a89d157a32b24afdc48b7eb865379abe7
-R a653c2e9383493624b2d8a6c82e92a37
+P c1d8a3f65490eef2216f360d708b1746cbaa6dadce42c0950dc8e09b9ab28ee2
+R f03dbc9beefc5d34628277d962365044
 U drh
-Z 02644c99894a777c23667de1b2c8f4f7
+Z 78c9dcb795a751d434058963c2b0384b
diff --git a/manifest.uuid b/manifest.uuid
index f9268007f6..65499fed89 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c1d8a3f65490eef2216f360d708b1746cbaa6dadce42c0950dc8e09b9ab28ee2
\ No newline at end of file
+ea748edecb261f2b862d542daff6e99a6fd8879a8ace94b440d99e110577d1c1
\ No newline at end of file
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 24fabe6276..5422007958 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3802,8 +3802,12 @@ void sqlite3MutexWarnOnContention(sqlite3_mutex*);
 #endif
 
 #ifndef SQLITE_OMIT_FLOATING_POINT
+# define EXP754 (((u64)0x7ff)<<52)
+# define MAN754 ((((u64)1)<<52)-1)
+# define IsNaN(X) (((X)&EXP754)==EXP754 && ((X)&MAN754)!=0)
   int sqlite3IsNaN(double);
 #else
+# define IsNaN(X)         0
 # define sqlite3IsNaN(X)  0
 #endif
 
diff --git a/src/util.c b/src/util.c
index 938b6a9fb2..31c88046e9 100644
--- a/src/util.c
+++ b/src/util.c
@@ -58,47 +58,11 @@ int sqlite3FaultSim(int iTest){
 #ifndef SQLITE_OMIT_FLOATING_POINT
 /*
 ** Return true if the floating point value is Not a Number (NaN).
-**
-** Use the math library isnan() function if compiled with SQLITE_HAVE_ISNAN.
-** Otherwise, we have our own implementation that works on most systems.
 */
 int sqlite3IsNaN(double x){
-  int rc;   /* The value return */
-#if !SQLITE_HAVE_ISNAN && !HAVE_ISNAN
-  /*
-  ** Systems that support the isnan() library function should probably
-  ** make use of it by compiling with -DSQLITE_HAVE_ISNAN.  But we have
-  ** found that many systems do not have a working isnan() function so
-  ** this implementation is provided as an alternative.
-  **
-  ** This NaN test sometimes fails if compiled on GCC with -ffast-math.
-  ** On the other hand, the use of -ffast-math comes with the following
-  ** warning:
-  **
-  **      This option [-ffast-math] should never be turned on by any
-  **      -O option since it can result in incorrect output for programs
-  **      which depend on an exact implementation of IEEE or ISO 
-  **      rules/specifications for math functions.
-  **
-  ** Under MSVC, this NaN test may fail if compiled with a floating-
-  ** point precision mode other than /fp:precise.  From the MSDN 
-  ** documentation:
-  **
-  **      The compiler [with /fp:precise] will properly handle comparisons 
-  **      involving NaN. For example, x != x evaluates to true if x is NaN 
-  **      ...
-  */
-#ifdef __FAST_MATH__
-# error SQLite will not work correctly with the -ffast-math option of GCC.
-#endif
-  volatile double y = x;
-  volatile double z = y;
-  rc = (y!=z);
-#else  /* if HAVE_ISNAN */
-  rc = isnan(x);
-#endif /* HAVE_ISNAN */
-  testcase( rc );
-  return rc;
+  u64 y;
+  memcpy(&y,&x,sizeof(y));
+  return IsNaN(y);
 }
 #endif /* SQLITE_OMIT_FLOATING_POINT */
 
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 98c50f362d..8dd2b421aa 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -3652,7 +3652,7 @@ u32 sqlite3VdbeSerialPut(u8 *buf, Mem *pMem, u32 serial_type){
 ** routine so that in most cases the overhead of moving the stack pointer
 ** is avoided.
 */ 
-static u32 SQLITE_NOINLINE serialGet(
+static u32 serialGet(
   const unsigned char *buf,     /* Buffer to deserialize from */
   u32 serial_type,              /* Serial type to deserialize */
   Mem *pMem                     /* Memory cell to write value into */
@@ -3684,7 +3684,7 @@ static u32 SQLITE_NOINLINE serialGet(
     assert( sizeof(x)==8 && sizeof(pMem->u.r)==8 );
     swapMixedEndianFloat(x);
     memcpy(&pMem->u.r, &x, sizeof(x));
-    pMem->flags = sqlite3IsNaN(pMem->u.r) ? MEM_Null : MEM_Real;
+    pMem->flags = IsNaN(x) ? MEM_Null : MEM_Real;
   }
   return 8;
 }