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Re: Altivec + 16 byte alignment
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- To: geoffk at geoffk dot org
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 11 Feb 03 14:06:22 EST
- Subject: Re: Altivec + 16 byte alignment
BIGGEST_ALIGNMENT is defined in the documentation as:
`BIGGEST_ALIGNMENT'
Biggest alignment that any data type can require on this machine,
in bits.
Right. That's what I mean that it's unclear. Code acts like it means the
largest alignment that can be guaranteed, but the above is ambiguous at best.
> If so, how *do* you find the largest alignment you can guarantee?
For error checking? MAX_OFILE_ALIGNMENT is probably the value you
want.
But that's even worse! It's *larger* than STACK_BOUNDARY.
My question is this: suppose a user says "I need this variable or type
aligned to an N bit boundary". How can you tell, as a function of N,
whether you can do that or not?