------- Additional Comments From dank at kegel dot com 2005-06-18 06:24 ------- Looks to me like gcc-3.4.3 is known to fail, too, depending on the CPU. Anthony Danalis and I came up with a little script to run foo4.i on various processors with various values for -mtune, which I'll attach; here are the results for four different x86 variants.
The last two columns are the time on gcc-3.4.3 and gcc-4.0.0 divided by the time on gcc-2.95.3, so any value above 1.0 in the last column is a performance regression. Rows are sorted by the last column. The first five rows represent performance regressions for gcc-3.4.3; the first three also represent performance regressions for gcc-4.0.0. family,model,name pic? tune [t_295, t_343, t_400] [t_295/t_295, t_343/t_295, t_400/t_295] 6,8, Pentium III (Coppermine), -fPIC athlon-xp [9.25, 16.22, 18.79] [1.00, 1.75, 2.03] 15,2, Xeon(TM) CPU 2.60GHz, -fPIC pentium4 [1.91, 3.89, 3.27] [1.00, 2.04, 1.71] 6,8, Pentium III (Coppermine), -fPIC pentium3 [9.15, 10.10, 13.20] [1.00, 1.10, 1.44] 15,2, Xeon(TM) CPU 2.60GHz, -fPIC athlon-xp [1.91, 2.00, 1.95] [1.00, 1.05, 1.02] 6,8, Pentium III (Coppermine), -fPIC pentium4 [9.27, 10.49, 8.87] [1.00, 1.13, 0.96] --- ok below this line --- 6,8, Pentium III (Coppermine), pentium4 [14.74, 13.71, 14.12] [1.00, 0.93, 0.96] 15,4, Athlon(tm) 64 3000+, -fPIC pentium4 [4.12, 3.68, 3.74] [1.00, 0.89, 0.91] 15,4, Pentium(R) 4 CPU 3.20GHz, -fPIC pentium4 [2.48, 2.18, 2.09] [1.00, 0.88, 0.84] 15,4, Athlon(tm) 64 3000+, -fPIC athlon-xp [4.12, 3.50, 3.20] [1.00, 0.85, 0.78] 15,4, Pentium(R) 4 CPU 3.20GHz, pentium4 [2.17, 1.07, 1.07] [1.00, 0.49, 0.49] 6,8, Pentium III (Coppermine), pentium3 [14.22, 6.26, 6.46] [1.00, 0.44, 0.45] 6,8, Pentium III (Coppermine), athlon-xp [14.93, 6.26, 6.27] [1.00, 0.42, 0.42] 15,4, Athlon(tm) 64 3000+, pentium4 [3.65, 1.39, 1.39] [1.00, 0.38, 0.38] 15,4, Athlon(tm) 64 3000+, athlon-xp [3.65, 1.39, 1.40] [1.00, 0.38, 0.38] 15,2, Xeon(TM) CPU 2.60GHz, pentium4 [6.42, 0.97, 0.98] [1.00, 0.15, 0.15] -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19923
