[Bug target/18665] [3.4/4.0 Regression] -ftrapv borks up simple integer arithmetic

[ebotcazou at gcc dot gnu dot org]

------- Additional Comments From ebotcazou at gcc dot gnu dot org  2004-12-10 10:11 -------
OK, I understand what happens: the 5 symbols __absvdi2, __addvdi3, __subvdi3,
__mulvdi3 and __negvdi2 are not #defined in libgcc2.h, hence not tweaked based
on the word size.  They are, therefore, double-word symbols everywhere, which
doesn't work on 64-bit targets.

The fix is straightforward, however there is a hitch: on 64-bit targets, libgcc
will contain 5 new symbols (__absvti2, __addvti3, __mulvti3, __negvti2,
__subvti3)  and will not contain (__absvsi2, __addvsi3, __mulvsi3, __negvsi2,
__subvsi3) anymore.  While the former is OK, the latter is probably not so we
might need to provide stubs that will redirect them to the equivalent mode-sized
routines for backwards compatibility.

Richard, does that sound plausible?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18665