Re: Misalignment of local SSE variables in thread function

[Jonathan Kinsey <jon_kinsey at hotmail dot com>]

Tim Prince wrote:
> I don't remember what was said in the past, but any gcc function which
> uses SSE parallel instructions must be called from a gcc function which
> passes a 16-byte aligned stack.  So you may be able to overcome it by
> interposing a wrapper function at the thread entry point (which does not
> use parallel SSE), with all gcc functions compiled with normal options
> (not -Os, which sets a smaller value in -mpreferred-stack-alignment). 
> To speculate further, possibly your pthreads library was compiled with
> options which don't pass 16-byte aligned stack.

Thanks for the reply - no help though:

By a wrapper function, if you mean for f() to call say g() - this makes
no difference (command line: gcc -msse test.c -otest.exe).

gcc doesn't seem to recognize -mpreferred-stack-alignment=8 as a valid
option.

I'm not using pthreads, so it's not that either.

Jon