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[Bug middle-end/31066] Suboptimal vectorization after inlining
- From: "jb at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 18 May 2007 21:11:17 -0000
- Subject: [Bug middle-end/31066] Suboptimal vectorization after inlining
- References: <bug-31066-10259@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #3 from jb at gcc dot gnu dot org 2007-05-18 22:11 -------
Closing as invalid. gfortran vectorizes the loop in gas_dyn:eos as it should.
The real reason why gfortran sucks at gas_dyn is that ifort uses the reciprocal
approximation instructions and a Newton-Rhapson step instead of division and
square root instructions. I.e. instead of calculating sqrt(a/b) which has both
a divide and a square root (both are pretty slow instructions) it calculates
1/sqrt(b*(1/a)) + the NR step. See PR31723.
--
jb at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jb at gcc dot gnu dot org
Status|NEW |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31066