Re: ix86 `double' alignment (was Re: egcs-1.1 release schedule)

[john at feith dot com (John Wehle)]

> Instead we must make sure that we always allocate stacks in 8 byte
> hunks in the prologue *and* that we push an extra dummy word on the stack
> when performing function calls where the arg list + return pointer
> are not a multiple of 8 bytes in size.

I'm seeing a lot of references to double and aligning on 8 byte boundaries.
As long as we are looking at this we may want to view it as a more general
problem.  I.e. Intel recommends that

  doubles be aligned on 8 byte boundarys

  long doubles be aligned on 16 byte boundarys

  objects >= 32 bytes in size be aligned on 32 byte boundarys

I believe that they all have similar issues with regards to encouraging
gcc to align them for optimal performance on the stack so it's possible
that they may all be "solved" with the same solution in the back end.

Just something to think about. :-)

-- John
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