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[Bug rtl-optimization/19680] sub-optimial register allocation with sse
- From: "tbptbp at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 9 May 2005 08:46:31 -0000
- Subject: [Bug rtl-optimization/19680] sub-optimial register allocation with sse
- References: <20050128233416.19680.tbptbp@gmail.com>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From tbptbp at gmail dot com 2005-05-09 08:46 -------
I'm going to ping this bugreport because there's still some very bad interaction
with gcse in current gcc.
Just compile the 'packet_intersection.cpp' testcase with ie g++-4.1-4120050501
for ia32 to convince yourself (x86-64 is apparently immune, thanks to the lower
register pressure).
It takes a bit of luck, or the use of -fno-gcse, to dodge that issue which
really kills performance.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19680