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[Bug fortran/47495] .mod files: File modification time - Makefile build issue
- From: "Joost.VandeVondele at pci dot uzh.ch" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sat, 29 Jan 2011 12:36:03 +0000
- Subject: [Bug fortran/47495] .mod files: File modification time - Makefile build issue
- Auto-submitted: auto-generated
- References: <bug-47495-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47495
--- Comment #9 from Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch> 2011-01-29 12:36:01 UTC ---
BTW, there is one thing I would still like to add, but I have not yet tried.
gfortran -fsyntax-only test.f90
will generate all .mod files 'defined' by test.f90
This seems like a great way to speedup parallel builds. Right now, make -j X
often serializes at '-O3 ....' because code generation is slow. Using a two
stage compile
test.mod: test.f90
gfortran -fsyntax-only test.f90
test.o: test.f90 test.mod
gfortran -c -O3 test.f90
could speed things up for large parallel projects since the next file can be
compiled (modded ?) as soon as the .mod of the previous one has been generated,
there is no need to wait for the .o.