From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 83415 invoked by alias); 22 Sep 2015 10:51:34 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 83351 invoked by uid 48); 22 Sep 2015 10:51:30 -0000 From: "ktietz at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/54412] Request for 32-byte stack alignment with -mavx on Windows Date: Tue, 22 Sep 2015 10:51:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 4.7.1 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: ktietz at gcc dot gnu.org X-Bugzilla-Status: SUSPENDED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_status cf_reconfirmed_on everconfirmed Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2015-09/txt/msg01773.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54412 Kai Tietz changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |SUSPENDED Last reconfirmed| |2015-09-22 Ever confirmed|0 |1 --- Comment #12 from Kai Tietz --- 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.