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[Bug target/54412] Request for 32-byte stack alignment with -mavx on Windows
- From: "ktietz at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 22 Sep 2015 10:51:28 +0000
- Subject: [Bug target/54412] Request for 32-byte stack alignment with -mavx on Windows
- Auto-submitted: auto-generated
- References: <bug-54412-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54412
Kai Tietz <ktietz at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |SUSPENDED
Last reconfirmed| |2015-09-22
Ever confirmed|0 |1
--- Comment #12 from Kai Tietz <ktietz at gcc dot gnu.org> ---
It is good to hear that issue is fixed for 32-bit. But for 64-bit - as I
already explained in comment above - this issue isn't fixable for
stack-variables.
The problem is that for x64 ABI we are tighten bound to SEH-prologue
information, and this can't express alignment-operations. The x64 ABI
guarantee 16 byte alignment on function entry, therefore sse 128-bit operations
are possible to be placed fully aligned on stack, but higher alignment is
simply not expressible.
Therefore I will need to set this bug to suspended. If this information gets
in future extended to allow such prologue-information we need for alignment,
then we will be able to fix that. So long it is suspended.