[Bug middle-end/45379] New: [4.6 Regression] ~10% slowdown on test_fpu at revision 163278

[dominiq at lps dot ens dot fr]

[macbook] lin/test% gfcp -v
Using built-in specs.
COLLECT_GCC=gfcp
COLLECT_LTO_WRAPPER=/opt/gcc/gcc4.6p/libexec/gcc/x86_64-apple-darwin10/4.6.0/lto-wrapper
Target: x86_64-apple-darwin10
Configured with: ../p_work/configure --prefix=/opt/gcc/gcc4.6p
--mandir=/opt/gcc/gcc4.6p/share/man --infodir=/opt/gcc/gcc4.6p/share/info
--build=x86_64-apple-darwin10 --host=x86_64-apple-darwin10
--target=x86_64-apple-darwin10 --enable-languages=c,fortran
--with-gmp=/opt/sw64 --with-libiconv-prefix=/opt/sw64 --with-system-zlib
--x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib
--with-cloog=/opt/sw64 --with-ppl=/opt/sw64 --with-mpc=/opt/sw64 --enable-lto
--enable-checking=release
Thread model: posix
gcc version 4.6.0 20100816 (experimental) [trunk revision 163277] (GCC) 
[macbook] lin/test% gfcp -Ofast -funroll-loops -fno-whole-file test_fpu.f90
[macbook] lin/test% time a.out
  Benchmark running, hopefully as only ACTIVE task
  0.99755959009261719     
Test1 - Gauss 2000 (101x101) inverts  2.0 sec  Err= 0.000000000000006
Test2 - Crout 2000 (101x101) inverts  2.9 sec  Err= 0.000000000000014
Test3 - Crout  2 (1001x1001) inverts  3.4 sec  Err= 0.000000000000043
Test4 - Lapack 2 (1001x1001) inverts  2.6 sec  Err= 0.000000000000250
                             total = 10.9 sec

11.080u 0.093s 0:11.18 99.9%    0+0k 0+0io 0pf+0w
[macbook] lin/test% gfcp -v
Using built-in specs.
COLLECT_GCC=gfcp
COLLECT_LTO_WRAPPER=/opt/gcc/gcc4.6p/libexec/gcc/x86_64-apple-darwin10/4.6.0/lto-wrapper
Target: x86_64-apple-darwin10
Configured with: ../p_work/configure --prefix=/opt/gcc/gcc4.6p
--mandir=/opt/gcc/gcc4.6p/share/man --infodir=/opt/gcc/gcc4.6p/share/info
--build=x86_64-apple-darwin10 --host=x86_64-apple-darwin10
--target=x86_64-apple-darwin10 --enable-languages=c,fortran
--with-gmp=/opt/sw64 --with-libiconv-prefix=/opt/sw64 --with-system-zlib
--x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib
--with-cloog=/opt/sw64 --with-ppl=/opt/sw64 --with-mpc=/opt/sw64 --enable-lto
--enable-checking=release
Thread model: posix
gcc version 4.6.0 20100816 (experimental) [trunk revision 163278] (GCC) 

[macbook] lin/test% gfcp -Ofast -funroll-loops -fno-whole-file test_fpu.f90
[macbook] lin/test% time a.out
  Benchmark running, hopefully as only ACTIVE task
  0.99755959009261719     
Test1 - Gauss 2000 (101x101) inverts  2.8 sec  Err= 0.000000000000006
Test2 - Crout 2000 (101x101) inverts  2.9 sec  Err= 0.000000000000014
Test3 - Crout  2 (1001x1001) inverts  3.4 sec  Err= 0.000000000000043
Test4 - Lapack 2 (1001x1001) inverts  2.8 sec  Err= 0.000000000000250
                             total = 11.8 sec

12.028u 0.095s 0:12.13 99.8%    0+0k 0+0io 0pf+0w

Note that for "Gauss 2000" alone the slowdown is ~40%.


-- 
           Summary: [4.6 Regression] ~10% slowdown on test_fpu at revision
                    163278
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dominiq at lps dot ens dot fr
 GCC build triplet: x86_64-apple-darwin10
  GCC host triplet: x86_64-apple-darwin10
GCC target triplet: x86_64-apple-darwin10


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45379