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| author | Daniel Black <daniel@linux.vnet.ibm.com> | 2017-11-17 08:00:32 +0800 |
|---|---|---|
| committer | Vicențiu-Marian Ciorbaru <vicentiu@mariadb.org> | 2018-08-22 09:39:30 +0300 |
| commit | 064ba8cc9f429fbf403f8d2c564e5f59f6799df9 (patch) | |
| tree | a85fddae1358a83104e35e782973793cedfba169 | |
| parent | 1b797e9e6308913c2472f3e04ad253e95a35d59f (diff) | |
| download | mariadb-git-064ba8cc9f429fbf403f8d2c564e5f59f6799df9.tar.gz | |
item_cmp_type: simplier for a faster codepath
The common case for this function is that both types are the same.
The Item_result defination from include/mysql.h.pp is the following enum
enum Item_result
{
STRING_RESULT=0, REAL_RESULT, INT_RESULT, ROW_RESULT, DECIMAL_RESULT,
TIME_RESULT
};
The compilers aren't quite smart enough to optimize to this shortcut so
this makes it quicker.
Before the change:
0000000000012730 <item_cmp_type(Item_result, Item_result)>:
12730: 89 f0 mov %esi,%eax
12732: 09 f8 or %edi,%eax
12734: 74 4c je 12782 <item_cmp_type(Item_result, Item_result)+0x52>
12736: 83 ff 02 cmp $0x2,%edi
12739: 75 0a jne 12745 <item_cmp_type(Item_result, Item_result)+0x15>
1273b: b8 02 00 00 00 mov $0x2,%eax
12740: 83 fe 02 cmp $0x2,%esi
12743: 74 3c je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
12745: 83 ff 03 cmp $0x3,%edi
12748: b8 03 00 00 00 mov $0x3,%eax
1274d: 74 32 je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
1274f: 83 fe 03 cmp $0x3,%esi
12752: 74 2d je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
12754: 83 ff 05 cmp $0x5,%edi
12757: b8 05 00 00 00 mov $0x5,%eax
1275c: 74 23 je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
1275e: 83 fe 05 cmp $0x5,%esi
12761: 74 1e je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
12763: 83 ff 04 cmp $0x4,%edi
12766: 74 05 je 1276d <item_cmp_type(Item_result, Item_result)+0x3d>
12768: 83 ff 02 cmp $0x2,%edi
1276b: 75 0f jne 1277c <item_cmp_type(Item_result, Item_result)+0x4c>
1276d: b8 04 00 00 00 mov $0x4,%eax
12772: 83 fe 02 cmp $0x2,%esi
12775: 74 0a je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
12777: 83 fe 04 cmp $0x4,%esi
1277a: 74 05 je 12781 <item_cmp_type(Item_result, Item_result)+0x51>
1277c: b8 01 00 00 00 mov $0x1,%eax
12781: c3 retq
12782: 31 c0 xor %eax,%eax
12784: c3 retq
After, noting the short cut and the beginning of the function:
0000000000012730 <item_cmp_type(Item_result, Item_result)>:
12730: 39 f7 cmp %esi,%edi
12732: 75 03 jne 12737 <item_cmp_type(Item_result, Item_result)+0x7>
12734: 89 f8 mov %edi,%eax
12736: c3 retq
12737: 83 ff 03 cmp $0x3,%edi
1273a: b8 03 00 00 00 mov $0x3,%eax
1273f: 74 32 je 12773 <item_cmp_type(Item_result, Item_result)+0x43>
12741: 83 fe 03 cmp $0x3,%esi
12744: 74 2d je 12773 <item_cmp_type(Item_result, Item_result)+0x43>
12746: 83 ff 05 cmp $0x5,%edi
12749: b8 05 00 00 00 mov $0x5,%eax
1274e: 74 23 je 12773 <item_cmp_type(Item_result, Item_result)+0x43>
12750: 83 fe 05 cmp $0x5,%esi
12753: 74 1e je 12773 <item_cmp_type(Item_result, Item_result)+0x43>
12755: 83 ff 04 cmp $0x4,%edi
12758: 74 05 je 1275f <item_cmp_type(Item_result, Item_result)+0x2f>
1275a: 83 ff 02 cmp $0x2,%edi
1275d: 75 0f jne 1276e <item_cmp_type(Item_result, Item_result)+0x3e>
1275f: b8 04 00 00 00 mov $0x4,%eax
12764: 83 fe 02 cmp $0x2,%esi
12767: 74 0a je 12773 <item_cmp_type(Item_result, Item_result)+0x43>
12769: 83 fe 04 cmp $0x4,%esi
1276c: 74 05 je 12773 <item_cmp_type(Item_result, Item_result)+0x43>
1276e: b8 01 00 00 00 mov $0x1,%eax
12773: c3 retq
Signed-off-by: Daniel Black <daniel@linux.vnet.ibm.com>
| -rw-r--r-- | sql/item.cc | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/sql/item.cc b/sql/item.cc index 0cf4864326f..745cbf31f0c 100644 --- a/sql/item.cc +++ b/sql/item.cc @@ -8719,13 +8719,11 @@ void Item_trigger_field::cleanup() Item_result item_cmp_type(Item_result a,Item_result b) { - if (a == STRING_RESULT && b == STRING_RESULT) - return STRING_RESULT; - if (a == INT_RESULT && b == INT_RESULT) - return INT_RESULT; - else if (a == ROW_RESULT || b == ROW_RESULT) + if (a == b) + return a; + if (a == ROW_RESULT || b == ROW_RESULT) return ROW_RESULT; - else if (a == TIME_RESULT || b == TIME_RESULT) + if (a == TIME_RESULT || b == TIME_RESULT) return TIME_RESULT; if ((a == INT_RESULT || a == DECIMAL_RESULT) && (b == INT_RESULT || b == DECIMAL_RESULT)) |