[Bug target/17836] New: [4.0 Regression] ABI breakage for 16-byte vectors (non-Altivec ABI & ISA)

[bonzini at gcc dot gnu dot org]

This bug was introduced when non-hardware-supported vectors were moved to BLKmode.

It was present in the i386 backend as well, and was fixed by
http://gcc.gnu.org/ml/gcc-patches/2004-07/msg02197.html; rth reviewed this patch
saying that "an rs6000 maintainer should review this to be sure that all vector
types of a given width should be treated identically".

The patch was subsequently updated and the update is at
http://gcc.gnu.org/ml/gcc-patches/2004-08/msg00379.html, together with an
analysis of all the backends that points out why the vector lowering patch does
not break other backends.

David Edelsohn rejected the patch, asking to provide a design for vector
argument passing; some of the discussions are at
- http://gcc.gnu.org/ml/gcc-patches/2004-08/msg00379.html
- http://gcc.gnu.org/ml/gcc-patches/2004-08/msg01531.html

I am including Mark in the CC list because I believe that (alas) this patch will
only be applied once 4.0 branches as an interim measure.

Paolo

-- 
           Summary: [4.0 Regression] ABI breakage for 16-byte vectors (non-
                    Altivec ABI & ISA)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: patch, ABI
          Severity: critical
          Priority: P1
         Component: target
        AssignedTo: bonzini at gcc dot gnu dot org
        ReportedBy: bonzini at gcc dot gnu dot org
                CC: dje at watson dot ibm dot com,gcc-bugs at gcc dot gnu
                    dot org,mark at codesourcery dot com
GCC target triplet: powerpc-apple-darwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17836