Summary: 40% slowdown when using LTO for a single-file program
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto

That's on a Intel Core(TM)2 Duo CPU E8400 @ 3.00GHz and using CentOS Linux 5.5
(x86-64)  with glibc-2.5-49.el5_5.2, binutils- and
gcc version 4.6.0 20100921 (experimental) [trunk revision 164472] (GCC)

The performance for fatigue of the Polyhedron test case drops by 40% if one
enables LTO (using -fwhole=program):

gfortran -march=native -ffast-math -funroll-loops -fwhole-program
-fno-protect-parens -O3

real    0m5.115s / user    0m5.071s / sys     0m0.015s

gfortran -march=native -ffast-math -funroll-loops -flto -fwhole-program
-fno-protect-parens -O3

real    0m7.225s / user    0m7.129s / sys     0m0.017s

For the other test cases, the results are mostly similar w/ and w/o LTO though
in tendency, the non-LTO version seems to be slightly slower (but also other
programs are running now thus the results are not 100% comparable with my
previous ones at )

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