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Subject: [Bug target/49001] GCC uses VMOVAPS/PD AVX instructions to access stack variables that are not 32-byte aligned
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49001

--- Comment #3 from Norbert Pozar <npozar at quick dot cz> 2011-05-16 06:05:37 UTC ---
(In reply to comment #1)
> Please provide testcase that can be compiled without changes. See [1].

I'm sorry about this.

> Probably mingw64 specific problem... CC added.

Thank you for your time to test the code on linux. I was worried that this
might be mingw64 specific.

(In reply to comment #2)
> Stack alignment isn't supported on Windows.

Since this bug effectively prevents using 256bit AVX instructions when
compiling for Windows using GCC, I was wondering if there are any plans to
support the stack alignment. It seems that simply adding 

andq    $-32, %rsp

to the function prologue would fix this. Or would it be feasible to replace
VMOVAPS by unaligned VMOVUPS when accessing the stack?