I can reproduce this bug as well on my feisty laptop (with all updates).
Compiling with -O1 works:
[EMAIL PROTECTED]:/tmp$ time g++ -O1 -c -o quickbook.o quickbook.cpp
real 0m29.831s
user 0m28.926s
sys 0m0.476s
Compiling with -O2 does not seem to end (I waited 15 minutes which I assume is
more than enough)
[EMAIL PROTECTED]:/tmp$ time g++ -O2 -c -o quickbook.o quickbook.cpp
(endless loop, or takes a very long time)
According to g++ man page:
-O2 turns on all optimization flags specified by -O. It also turns
on the following optimization flags: -fthread-jumps -fcrossjumping
-foptimize-sibling-calls -fcse-follow-jumps -fcse-skip-blocks
-fgcse -fgcse-lm -fexpensive-optimizations -fstrength-reduce -fre‐
run-cse-after-loop -frerun-loop-opt -fcaller-saves -fpeephole2
-fschedule-insns -fschedule-insns2 -fsched-interblock
-fsched-spec -fregmove -fstrict-aliasing
-fdelete-null-pointer-checks -freorder-blocks -freorder-functions
-falign-functions -falign-jumps -falign-loops -falign-labels
-ftree-vrp -ftree-pre
So I tried adding on top of -O1, all optimisation turned on by O2, in order to
find the one which causes the bug.
However, adding them all on top of -O1 does not trigger the bug:
[EMAIL PROTECTED]:/tmp$ time g++ -O1 -fthread-jumps -fcrossjumping
-foptimize-sibling-calls -fcse-follow-jumps -fcse-skip-blocks -fgcse
-fgcse-lm -fexpensive-optimizations -fstrength-reduce -frerun-cse-after-
loop -frerun-loop-opt -fcaller-saves -fpeephole2 -fschedule-insns
-fschedule-insns2 -fsched-interblock -fsched-spec -fregmove -fstrict-
aliasing -fdelete-null-pointer-checks -freorder-blocks -freorder-
functions -falign-functions -falign-jumps -falign-loops -falign-labels
-ftree-vrp -ftree-pre -c -o quickbook.o quickbook.cpp
real 0m39.420s
user 0m38.382s
sys 0m0.560s
Does it mean -O2 turns on optimisations that are not documented in g++
man page?
--
g++: infinite loop with -O3 while compiling Boost.Quickbook from Boost CVS
https://bugs.launchpad.net/bugs/82404
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