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[Bug target/50135] Loop optimization.
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sun, 21 Aug 2011 10:25:31 +0000
- Subject: [Bug target/50135] Loop optimization.
- Auto-submitted: auto-generated
- References: <bug-50135-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50135
Uros Bizjak <ubizjak at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |SUSPENDED
Last reconfirmed| |2011-08-21
Ever Confirmed|0 |1
--- Comment #2 from Uros Bizjak <ubizjak at gmail dot com> 2011-08-21 10:25:31 UTC ---
Don't worry about loop insn, it is *SLOW* on every half-decent recent
processor, see instruction_tables.pdf at [1]. OTOH, the insn has only short
jump displacement, so you are out of luck for every loop larger than 128 bytes.
So, until x86 implements something like powerpc bdnz insn, there will be no
doloop_* patterns.
[1] http://agner.org/optimize/