AltiVec [RFH] Overload resolution of vec_subs intrinsic fails

Paolo Bonzini bonzini@gnu.org
Sat Apr 10 09:33:00 GMT 2004


> No.  I mentioned at the time that we should probably recurse
> on compatibility.


I have this (and the removal of unneeded vector modes) implemented in
tree-ssa.  I'm waiting for the merge (actually I need tree-profiling in order
to have the CFG at -O0, but this can be changed).

Anyway, unsigned types are compatible with signed ones, aren't them? So the
bug would remain.  And I remember that making unsigned and signed types
incompatible caused regressions: see this excerpt from
http://gcc.gnu.org/ml/gcc-patches/2004-03/msg00843.html

    "The same is for gcc.dg/simd-1.c and gcc.dg/20020531-1.c, where one was
    checking for incompatibility between vector types with different
    signedness but the same mode, and the other was happily passing an
    unsigned V8QI to __builtin_ia32_paddusb which expects a signed V8QI.
    I fixed gcc.dg/simd-1.c to not expect an error on vector types with
    the same mode but different signedness."

That's the problematic part.

Paolo




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