[Bug tree-optimization/83262] SELECT CASE slower than IF/ELSE

["tkoenig at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83262

--- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
ig25@linux-d6cw:~> gfortran -v
Es werden eingebaute Spezifikationen verwendet.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/home/ig25/lib/gcc/x86_64-pc-linux-gnu/8.0.0/lto-wrapper
Ziel: x86_64-pc-linux-gnu
Konfiguriert mit: ../trunk/configure --prefix=/home/ig25
--enable-maintainer-mode --enable-languages=c,c++,fortran --disable-multilib
Thread-Modell: posix
gcc-Version 8.0.0 20171127 (experimental) (GCC)

ig25@linux-d6cw:~> cat /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Core(TM)2 Quad  CPU   Q8200  @ 2.33GHz
stepping        : 7
microcode       : 0x70a
cpu MHz         : 1998.000
cache size      : 2048 KB

Using PowerPC, I get 

[tkoenig@gcc1-power7 ~]$ ./a.out 100000000 200000000 30000000
 Number of input arguments:            3
          GOTO: n =100000000, ss =-0.1480800E+10, time =    0.441 (s)
   SELECT CASE: n =100000000, ss =-0.1480800E+10, time =    0.412 (s)
       IF-Goto: n =100000000, ss =-0.1480800E+10, time =    0.318 (s)
     IF-noGoto: n =100000000, ss =-0.1480800E+10, time =    0.176 (s)
       IF-ELSE: n =100000000, ss =-0.1480800E+10, time =    1.358 (s)

          GOTO: n =200000000, ss =-0.2961600E+10, time =    1.372 (s)
   SELECT CASE: n =200000000, ss =-0.2961600E+10, time =    0.647 (s)
       IF-Goto: n =200000000, ss =-0.2961600E+10, time =    0.382 (s)
     IF-noGoto: n =200000000, ss =-0.2961600E+10, time =    0.338 (s)
       IF-ELSE: n =200000000, ss =-0.2961600E+10, time =    0.392 (s)

          GOTO: n = 30000000, ss =-0.4442400E+09, time =    0.108 (s)
   SELECT CASE: n = 30000000, ss =-0.4442400E+09, time =    0.092 (s)
       IF-Goto: n = 30000000, ss =-0.4442400E+09, time =    0.051 (s)
     IF-noGoto: n = 30000000, ss =-0.4442400E+09, time =    0.051 (s)
       IF-ELSE: n = 30000000, ss =-0.4442400E+09, time =    0.054 (s)

           GOTO costs totally     1.920 (s)
    SELECT CASE costs totally     1.151 (s)
        IF-Goto costs totally     0.752 (s)
      IF-noGoto costs totally     0.564 (s)
        IF-ELSE costs totally     1.804 (s)
    Total time:    6.191 (s)

with

[tkoenig@gcc1-power7 ~]$ gfortran -v
Es werden eingebaute Spezifikationen verwendet.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/home/tkoenig/libexec/gcc/powerpc64-unknown-linux-gnu/8.0.0/lto-wrapper
Ziel: powerpc64-unknown-linux-gnu
Konfiguriert mit: ../trunk/configure --prefix=/home/tkoenig
--enable-languages=fortran,c,c++ --disable-multilib --enable-maintainer-mode
Thread-Modell: posix
gcc-Version 8.0.0 20171108 (experimental) (GCC)