Re: PATCH: PR target/35657: TDmode isn't aligned at 128bit when passing to a function

[Mark Mitchell <mark at codesourcery dot com>]

H.J. Lu wrote:

> The main problem is that the exiting ia32 psABI doesn't cover any new
> hardware/software features and there are no updates to support them.
> I am working on a solution.

The problem is that features went into the compiler without an ABI 
design being finalized.  It's not a question of the official ABI 
documents; it's a question of doing the design and sticking to it.

As someone who broke the C++ ABI for years, I'm fully aware of how hard 
this is -- and also how much pain it can cause. :-(

It's always exciting to check in new features, but putting out 
unfinished features to the world makes us look bad.  While we look at it 
as "Hey, here's an X, that shows people we're working on it, people may 
help us with it, some people may be able to use it", many of our users 
say "They have a broken X; that sucks."  ABI breakage sends the message 
that we're not serious about supporting long-term use, and that's a 
negative.

I'm not trying to pick on you; this happens sometimes.  I just think we 
need to try to be very sensitive to the issue.

--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713