https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115855
Bug ID: 115855
Summary: Slow compilation of Firefox with -O2 (in callgraph
expansion)
Product: gcc
Version: unknown
Status: UNCONFIRMED
Keywords: compile-time-hog
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
Target Milestone: ---
Using the original testcase from PR115836, compilation takes a large amount of
time. It comes from Firefox.
With `g++ -c gl.ii -m32 -Wno-attributes -ftime-report`, I get:
```
real 0m48.348s
user 0m39.089s
sys 0m8.994s
```
With `g++ -c gl.ii -m32 -Wno-attributes -ftime-report -O2`, I get:
```
real 1m23.516s
user 1m8.139s
sys 0m14.896s
```
This is with a checking compiler though so testing with =release would be
appreciated.
With -O2:
```
[...]
phase opt and generate : 63.81 ( 94%) 11.82 ( 81%) 76.07 ( 92%)
1622M ( 80%)
|name lookup : 0.54 ( 1%) 0.38 ( 3%) 1.17 ( 1%)
7911k ( 0%)
|overload resolution : 1.01 ( 1%) 0.39 ( 3%) 1.52 ( 2%)
119M ( 6%)
garbage collection : 3.38 ( 5%) 0.13 ( 1%) 3.54 ( 4%)
0 ( 0%)
dump files : 0.77 ( 1%) 0.33 ( 2%) 0.99 ( 1%)
0 ( 0%)
callgraph construction : 0.37 ( 1%) 0.18 ( 1%) 0.54 ( 1%)
51M ( 3%)
callgraph optimization : 0.79 ( 1%) 0.30 ( 2%) 1.04 ( 1%)
108k ( 0%)
callgraph functions expansion : 46.08 ( 68%) 5.71 ( 39%) 52.10 ( 63%)
960M ( 48%)
callgraph ipa passes : 16.33 ( 24%) 5.67 ( 39%) 22.13 ( 27%)
544M ( 27%)
[...]
```
