https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60243
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jamborm at gcc dot gnu.org
--- Comment #21 from Richard Biener <rguenth at gcc dot gnu.org> ---
Current trunk at -O2 -fno-checking (w/ otherwise checking enabled):
Time variable usr sys wall
GGC
phase setup : 0.00 ( 0%) 0.00 ( 0%) 0.00 ( 0%)
1245 kB ( 0%)
phase parsing : 16.72 ( 6%) 15.15 ( 75%) 31.86 ( 10%)
612162 kB ( 18%)
phase opt and generate : 272.51 ( 94%) 5.08 ( 25%) 277.63 ( 90%)
2719266 kB ( 82%)
ipa inlining heuristics : 31.82 ( 11%) 0.00 ( 0%) 31.85 ( 10%)
0 kB ( 0%)
ipa profile : 9.92 ( 3%) 0.00 ( 0%) 9.93 ( 3%)
0 kB ( 0%)
ipa SRA : 153.77 ( 53%) 1.81 ( 9%) 155.54 ( 50%)
741949 kB ( 22%)
early inlining heuristics : 24.54 ( 8%) 0.03 ( 0%) 24.65 ( 8%)
2987 kB ( 0%)
at -O -g we can also see to my surprise:
tree CFG construction : 6.27 ( 4%) 0.04 ( 0%) 6.28 ( 4%)
628095 kB ( 15%)
tree operand scan : 3.78 ( 3%) 0.99 ( 4%) 5.01 ( 3%)
47597 kB ( 1%)
tree CFG cleanup : 7.51 ( 5%) 0.05 ( 0%) 7.71 ( 5%)
0 kB ( 0%)
the tree CFG construction time is _entirely_ spent in assign_discriminators!
That's because expand_location is costly and the discriminator_per_locus
hashtable does that all the time. It's also because the testcase
sits on a single line. The whole code seems odd to me as well given
it doesn't very well handle trailing or leading UNKNOWN_LOCATION stmts.
I also wonder why it is done at CFG construction time.
The IPA SRA time is all spent in compute_fn_summary via convert_callers.
Not sure why that's necessary here? Martin, in r152368 you reduced those
to once-per-caller but obviously if each function calls each other function
as in this testcase this is still O(n^2). Why's the summary not simply
recomputed when we process the caller next? Thus at most N times?
