https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63577
Bug ID: 63577
Summary: [4.8/4.9/5? Regression]: Huge compile time and memory
usage with -O and not -fPIC
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: jfsoden at mpp dot mpg.de
Created attachment 33749
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33749&action=edit
Test program.
The attached Fortran programs compiles slowly and needs lots of memory
if compiled with basic optimization (-O) but without -fPIC.
With -fPIC, memory usage and compile time are much shorter.
$ gfortran abbrevd408h0.f90 -c -O
needs 45s and 630MB RAM
but
$ gfortran abbrevd408h0.f90 -c -O -fPIC
needs only 6s and 105MB RAM.
$ gfortran abbrevd408h0.f90 -c
works also quickly.
The attached file is shortened. On the full file, the effect is more distinct
(with gfortran 4.8.1: >8GB RAM usage, several minutes).
With gfortran 4.7, the issue does not appear.
Used version:
GNU Fortran (Debian 4.9.1-17) 4.9.1 [~ SVN r216240]
Also
GNU Fortran (SUSE Linux) 4.8.1 20130909 [gcc-4_8-branch revision 202388]
GNU Fortran (SUSE Linux) 4.8.3 20140627 [gcc-4_8-branch revision 212064]
are affected.
