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Re: [PATCH] Fix issue with RTL alias-export and promoted subregs


On 09/28/2009 02:59 AM, Richard Guenther wrote:
There's some weird things going on with stack slot allocations.
x is allocated from [virtual-stack-vars, virtual-stack-vars + 18]
and y is allocated from [virtual-stack-vars + 19, virtual-stack-vars + 34]
for some reason (so&y - 3 is DImode aligned, as is&x)!?

How is that weird? They're both 19 byte, 8-bit aligned structures.
Admittedly, things would be more efficient if we over-allocated to make them 20 byte, 32-bit aligned structures.


note how it carefully tries to avoid changing values after x

Yeah, well... what are you supposed to do if you don't have 1 or 2-byte stores? If you were to compile with -mbwx to enable those instructions, you'd find all of that ugliness gone.



r~



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