[Bug target/35657] TDmode isn't aligned at 128bit when passing to a function

[ubizjak at gmail dot com]

------- Comment #1 from ubizjak at gmail dot com  2008-03-21 20:53 -------
(In reply to comment #0)
> ix86_function_arg_boundary returns PARM_BOUNDARY for TDmode
> for ia32. Should it return 128bit? The psABI isn't clear on
> it. I think it should be aligned at 128bit.

Yes, because it is moved to/from XMM registers. Currently, this exact problem
is handled by a specialization code in ix86_expand_vector_move that forces
unaligned instructions for TDmode memory moves via
ix86_expand_vector_move_misalign.

Please note that we have to be compatible with SSE x86 and non-SSE x86 code, so
TDmode can't be passed in XMM registers on x86_32 targets.

I'd wait for psABI to clear situation w.r.t to alignment first.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35657