https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60243
--- Comment #26 from Martin Jambor <jamborm at gcc dot gnu.org> ---
With new IPA-SRA, the situation has improved quite a bit, see below
where old-ipa-sra is trunk r275981 and new-ipa-sra is trunk r275982
(arrival of new IPA-SRA):
$ /usr/bin/time -f 'real=%e user=%U' taskset -c 0
~/gcc/old-ipa-sra/inst/bin/gcc -O0 -fno-inline -S pr60243.c
real=64.20 user=63.37
$ /usr/bin/time -f 'real=%e user=%U' taskset -c 0
~/gcc/old-ipa-sra/inst/bin/gcc -O1 -fno-inline -S pr60243.c
real=90.80 user=89.84
$ /usr/bin/time -f 'real=%e user=%U' taskset -c 0
~/gcc/old-ipa-sra/inst/bin/gcc -O2 -S pr60243.c
real=235.18 user=233.77
$ /usr/bin/time -f 'real=%e user=%U' taskset -c 0
~/gcc/old-ipa-sra/inst/bin/gcc -O2 -fno-inline -S pr60243.c
real=198.59 user=197.27
$ /usr/bin/time -f 'real=%e user=%U' taskset -c 0
~/gcc/new-ipa-sra/inst/bin/gcc -O2 -S pr60243.c
real=114.68 user=113.76
$ /usr/bin/time -f 'real=%e user=%U' taskset -c 0
~/gcc/new-ipa-sra/inst/bin/gcc -O2 -fno-inline -S pr60243.c
real=88.40 user=87.41
$ taskset -c 0 ~/gcc/new-ipa-sra/inst/bin/gcc -O2 -S pr60243.c -ftime-report
(showing only IPA passes and passes taking more than 1% of usr time)
phase parsing : 9.57 ( 8%) 6.93 ( 75%) 16.51 ( 13%)
655448 kB ( 20%)
phase opt and generate : 105.13 ( 92%) 2.34 ( 25%) 107.83 ( 87%)
2619926 kB ( 80%)
callgraph functions expansion : 18.05 ( 16%) 1.34 ( 14%) 19.71 ( 16%)
302442 kB ( 9%)
callgraph ipa passes : 77.51 ( 68%) 0.50 ( 5%) 78.06 ( 63%)
623696 kB ( 19%)
ipa function summary : 0.15 ( 0%) 0.01 ( 0%) 0.16 ( 0%)
1494 kB ( 0%)
ipa dead code removal : 0.32 ( 0%) 0.00 ( 0%) 0.29 ( 0%)
0 kB ( 0%)
ipa cp : 1.10 ( 1%) 0.05 ( 1%) 1.13 ( 1%)
326688 kB ( 10%)
ipa inlining heuristics : 17.85 ( 16%) 0.06 ( 1%) 17.82 ( 14%)
83762 kB ( 3%)
ipa function splitting : 0.00 ( 0%) 0.00 ( 0%) 0.03 ( 0%)
0 kB ( 0%)
ipa various optimizations : 0.63 ( 1%) 0.28 ( 3%) 0.96 ( 1%)
131752 kB ( 4%)
ipa reference : 0.06 ( 0%) 0.00 ( 0%) 0.06 ( 0%)
0 kB ( 0%)
ipa profile : 14.66 ( 13%) 0.00 ( 0%) 14.67 ( 12%)
0 kB ( 0%)
ipa pure const : 0.36 ( 0%) 0.04 ( 0%) 0.60 ( 0%)
0 kB ( 0%)
ipa icf : 0.17 ( 0%) 0.01 ( 0%) 0.19 ( 0%)
0 kB ( 0%)
ipa SRA : 0.21 ( 0%) 0.00 ( 0%) 0.23 ( 0%)
102 kB ( 0%)
ipa free inline summary : 0.05 ( 0%) 0.00 ( 0%) 0.04 ( 0%)
0 kB ( 0%)
preprocessing : 4.20 ( 4%) 3.31 ( 36%) 7.77 ( 6%)
384133 kB ( 12%)
lexical analysis : 2.46 ( 2%) 1.80 ( 19%) 3.95 ( 3%)
0 kB ( 0%)
parser function body : 2.71 ( 2%) 1.82 ( 20%) 4.57 ( 4%)
269874 kB ( 8%)
early inlining heuristics : 12.82 ( 11%) 0.03 ( 0%) 12.71 ( 10%)
4031 kB ( 0%)
inline parameters : 8.01 ( 7%) 0.12 ( 1%) 8.27 ( 7%)
30845 kB ( 1%)
tree CFG construction : 5.23 ( 5%) 0.04 ( 0%) 5.03 ( 4%)
628095 kB ( 19%)
tree SSA rewrite : 3.42 ( 3%) 0.02 ( 0%) 3.39 ( 3%)
93305 kB ( 3%)
tree operand scan : 17.53 ( 15%) 0.26 ( 3%) 17.77 ( 14%)
96568 kB ( 3%)
Essentially, -O2 -fno-inline is now as fast as -O1 -fno-inline.
