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From: "janis at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/34526] New: no-altivec ABI should be fixed or no longer be the default Date: Tue, 18 Dec 2007 21:56:00 -0000 [thread overview] Message-ID: <bug-34526-4503@http.gcc.gnu.org/bugzilla/> (raw) This PR is meant to be a central place to record information about this issue. The default ABI for 32-bit PowerPC GNU/Linux does not pass vectors in AltiVec registers and does not save and restore AltiVec registers in functions that use those registers. With -mabi=altivec, vectors are passed in AltiVec registers and AltiVec registers used within a function are saved and restored. This has always been a problem if multiple functions in a call chain use AltiVec registers without the AltiVec ABI, but it's become a more visible issue with -ftree-vectorize included in -O3, particularly when the user specifies a CPU that supports AltiVec and might not realize that those two options imply that AltiVec registers will likely be used in multiple functions in a call stack without saving and restoring them. Two recent PRs that are due to this problem are 34038 and 34437. A somewhat-rel ated PR is 33899. There were some recent discussions of this issue: http://gcc.gnu.org/ml/gcc-patches/2007-07/msg02159.html http://gcc.gnu.org/ml/gcc-patches/2007-08/msg00438.html This ought to be fixed either by using the AltiVec ABI by default or by changing the non-AltiVec ABI to save and restore AltiVec registers in functions that use them. -- Summary: no-altivec ABI should be fixed or no longer be the default Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: janis at gcc dot gnu dot org GCC target triplet: powerpc-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34526
next reply other threads:[~2007-12-18 21:56 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-12-18 21:56 janis at gcc dot gnu dot org [this message] 2007-12-19 18:50 ` [Bug target/34526] " janis at gcc dot gnu dot org 2008-01-25 23:32 ` janis at gcc dot gnu dot org 2008-01-25 23:35 ` janis at gcc dot gnu dot org 2008-01-30 0:07 ` janis at gcc dot gnu dot org 2008-01-30 5:19 ` janis at gcc dot gnu dot org 2008-02-04 21:29 ` janis at gcc dot gnu dot org 2008-02-05 2:24 ` janis at gcc dot gnu dot org 2008-02-05 3:19 ` drow at gcc dot gnu dot org 2008-02-07 2:05 ` janis at gcc dot gnu dot org 2008-02-07 18:22 ` janis at gcc dot gnu dot org 2008-02-12 1:36 ` janis at gcc dot gnu dot org 2008-02-14 16:32 ` drow at gcc dot gnu dot org 2008-02-22 1:57 ` janis at gcc dot gnu dot org 2008-02-22 1:59 ` janis at gcc dot gnu dot org 2009-05-14 5:35 ` bje at gcc dot gnu dot org 2009-05-14 16:51 ` janis at gcc dot gnu dot org
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