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[Bug tree-optimization/37194] Autovectorization of small constant iteration loop degrades performance
- From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 21 Aug 2008 19:32:01 -0000
- Subject: [Bug tree-optimization/37194] Autovectorization of small constant iteration loop degrades performance
- References: <bug-37194-14936@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #1 from pinskia at gcc dot gnu dot org 2008-08-21 19:32 -------
Confirmed, this is true for the Cell too. In fact is bad for the cell because
of:
stfs 1,16(1)
cmpwi 7,0,0
li 0,16
slwi 9,9,2
li 11,0
add 9,3,9
lvewx 0,1,0
vspltw 0,0,0
The store is not 40-50 cycles before the load so we have a LHS.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |pinskia at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
GCC build triplet|powerpc64-linux |
GCC host triplet|powerpc64-linux |
Keywords| |missed-optimization
Last reconfirmed|0000-00-00 00:00:00 |2008-08-21 19:32:00
date| |
Summary|Autovectorization of |Autovectorization of small
|constant iteration loop |constant iteration loop
|degrades performance |degrades performance
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37194