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From: "christophe.lyon at st dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug other/51450] New: configure's test for -fno-rtti -fno-exceptions broken
Date: Wed, 07 Dec 2011 14:14:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51450

             Bug #: 51450
           Summary: configure's test for -fno-rtti -fno-exceptions broken
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: christophe.lyon@st.com


I have noticed that configure decides that my build GCC does not support
-fno-rtti -fno-exceptions when building a new GCC.

I traced this down to a problem in libtool.m4 where _LT_COMPILER_NO_RTTI uses
_LT_COMPILER_OPTION to check whether these 2 options are supported.

The latter compiles & links $lt_simple_compile_test_code which contains:
lt_simple_compile_test_code="int some_variable = 0;"

The link phase fails because there is no main(), and then configure decides
-fno-rtti -fno-exceptions are not supported.

I am not sure about how to fix this:
- change _LT_COMPILER_OPTION to use $lt_simple_link_test_code instead?
- use a modified _LT_LINKER_OPTION (given that the options tests belong to
CFLAGS rather than LDFLAGS)?
- other?

Maybe this bug should be reported elsewhere?