https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84130
Bug ID: 84130
Summary: excessive compile time with -O1
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dcb314 at hotmail dot com
Target Milestone: ---
Created attachment 43293
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43293&action=edit
gzipped C++ source code
For the attached C++ code and the following shell script
time /home/dcb/gcc/results.257131.release/bin/g++ -O0 -w -c bug415.cc
time /home/dcb/gcc/results.257131.release/bin/g++ -O1 -w -c bug415.cc
time /home/dcb/gcc/results.257131.release/bin/g++ -O2 -w -c bug415.cc
With a release build of gcc trunk revision 257131, I got the following
numbers:
real 0m29.298s
user 0m28.299s
sys 0m0.724s
real 1m56.663s
user 1m54.380s
sys 0m1.157s
real 3m7.535s
user 3m5.559s
sys 0m1.065s
Going from -O0 to -O1 seems excessive. -ftime-report seems to suggest
most of the time is spent in
phase opt and generate : 110.71 (97%) usr 5.84 (85%) sys 117.63 (96%) wall
2
972042 kB (88%) ggc
