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[Bug target/49001] GCC uses VMOVAPS/PD AVX instructions to access stack variables that are not 32-byte aligned
- From: "npozar at quick dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 16 May 2011 06:14:06 +0000
- Subject: [Bug target/49001] GCC uses VMOVAPS/PD AVX instructions to access stack variables that are not 32-byte aligned
- Auto-submitted: auto-generated
- References: <bug-49001-4@http.gcc.gnu.org/bugzilla/>
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?