http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50272
Bug #: 50272
Summary: A case that PRE optimization hurts performance
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Pri
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50272
--- Comment #1 from Jiangning Liu 2011-09-02
05:11:38 UTC ---
Richard gave some analysis at http://gcc.gnu.org/ml/gcc/2011-08/msg00037.html
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38644
--- Comment #56 from Jiangning Liu 2011-10-31
07:48:25 UTC ---
(In reply to comment #54)
> I tested with GCC 4.6.2 and the patch provided by Mikael Pettersson. It works
> for -march=armv4t and -march=armv5t, but not for -march=armv5te:
>
Sebas
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39976
--- Comment #44 from Jiangning Liu 2012-02-24
08:09:25 UTC ---
I'm not sure if this kind of bug has been completely fixed, and posted a
qeustion in mail list at http://gcc.gnu.org/ml/gcc/2012-02/msg00415.html .
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52424
--- Comment #1 from Jiangning Liu 2012-02-29
03:23:46 UTC ---
> I've attached a proposed fix. Jiangning, can you please apply this and see if
> your performance problem is resolved?
Bill,
Confirmed, I think your patch works for my big case and
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52424
--- Comment #2 from Jiangning Liu 2012-02-29
03:42:17 UTC ---
> Jiangning Liu reported that the following C code has recently experienced
> degraded performance on trunk. (Jiangning, please fill in the
> Host/Target/Build fields for your configu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52563
--- Comment #3 from Jiangning Liu 2012-03-13
08:11:40 UTC ---
First, I tried gcc 4.4.3 on x86-64, and it works for this test case, so it is
to some extension a GCC regression.
Second, I tried trunk, and I can reproduce the failure for this test
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38644
Jiangning Liu changed:
What|Removed |Added
CC||jiangning.liu at arm dot
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38644
--- Comment #41 from Jiangning Liu 2011-08-09
02:04:52 UTC ---
> Yes, this is from the libstdc++ sources (4.6.1 20110627,
> libstdc++-v3/libsupc++/new_opnt.cc). You need a non-EABI ARM variant of GCC
> since this bug manifestation will only sho
