------- Comment #3 from dominiq at lps dot ens dot fr 2009-12-08 18:31 -------
(In reply to comment #2)
> I don't think that's the right approach, that would only mask the bug in the
> testsuite but leave it in userland. ...
You are right, but from what follows I think the problem comes from the way the
additional libs are passed to collect2.
First, without -lm, gcc45 uses the following collect2:
/opt/gcc/gcc4.5w/libexec/gcc/x86_64-apple-darwin10/4.5.0/collect2 -dynamic
-arch x86_64 -macosx_version_min 10.6.2 -weak_reference_mismatches non-weak -o
a.out -lcrt1.10.5.o -L/opt/gcc/gcc4.5w/lib/gcc/x86_64-apple-darwin10/4.5.0
-L/opt/gcc/gcc4.5w/lib/gcc/x86_64-apple-darwin10/4.5.0/../../.. pr42074.o
-lgcc_s.10.5 -lgcc_ext.10.5 -lgcc -no_compact_unwind -lSystem
and the test succeed.
Second, if I add -lm, I get
/opt/gcc/gcc4.5w/libexec/gcc/x86_64-apple-darwin10/4.5.0/collect2 -dynamic
-arch x86_64 -macosx_version_min 10.6.2 -weak_reference_mismatches non-weak -o
a.out -lcrt1.10.5.o -L/opt/gcc/gcc4.5w/lib/gcc/x86_64-apple-darwin10/4.5.0
-L/opt/gcc/gcc4.5w/lib/gcc/x86_64-apple-darwin10/4.5.0/../../.. pr42074.o -lm
-lgcc_s.10.5 -lgcc_ext.10.5 -lgcc -no_compact_unwind -lSystem
and the text fails. Note that -lm is passed before "-lgcc_s.10.5 -lgcc_ext.10.5
-lgcc -no_compact_unwind -lSystem".
Third, libm.dylib is a symlink to libSystem.dylib
lrwxr-xr-x 1 root wheel 15 Aug 14 22:47 /usr/lib/libm.dylib -> libSystem.dylib*
so -lm seems redundant.
Fourth, I see
[macbook] f90/bug% otool -L /usr/lib/libSystem.dylib
/usr/lib/libSystem.dylib:
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
version 125.0.0)
/usr/lib/system/libmathCommon.A.dylib (compatibility version 1.0.0,
current version 315.0.0)
[macbook] f90/bug% nm /usr/lib/libSystem.B.dylib | grep divdc3
0019fa1e S $ld$hide$os10.4$___divdc3
0019fa1f S $ld$hide$os10.5$___divdc3
001640d0 T ___divdc3
Five, If I don't use -lm, but place -lSystem before "-lgcc_s.10.5
-lgcc_ext.10.5 -lgcc -no_compact_unwind" as in
[macbook] f90/bug%
/opt/gcc/gcc4.5w/libexec/gcc/x86_64-apple-darwin10/4.5.0/collect2 -dynamic
-arch x86_64 -macosx_version_min 10.6.2 -weak_reference_mismatches non-weak -o
a.out -lcrt1.10.5.o -L/opt/gcc/gcc4.5w/lib/gcc/x86_64-apple-darwin10/4.5.0
-L/opt/gcc/gcc4.5w/lib/gcc/x86_64-apple-darwin10/4.5.0/../../.. pr42074.o
-lSystem -lgcc_s.10.5 -lgcc_ext.10.5 -lgcc -no_compact_unwind
the test abort.
My uneducated conclusions are first, that -lm is redundant with -lSystem and
probably should never be used (unless you ask for trouble), second, ___divdc3
uses a lazy complex division (a bug to be reported upstream!-), third, the way
additional libs are passed to collect2 is probably right if one wants to
overwrite functions in the default libs.
I have now access to intel-darwin9 and I'll see what going on for it after
dinner time.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42333
