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From: "joseph at codesourcery dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/63764] [5 Regression] ICE: in verify_ssa, at tree-ssa.c:939
Date: Tue, 18 Nov 2014 16:55:00 -0000 [thread overview]
Message-ID: <bug-63764-4-veXvAEVs1e@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-63764-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63764
--- Comment #9 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Tue, 18 Nov 2014, jakub at gcc dot gnu.org wrote:
> > Maybe build_array_ref needs to ensure that references to elements of
> > non-lvalue vectors don't become lvalues? (This would be different to
> > non-lvalue arrays arising from non-lvalue structs and unions, where the
> > result of an array reference *is* an lvalue but modifying it, or accessing
> > it after the next sequence point, has undefined behavior.)
>
> Apparently I misremembered it, trying it again, I see the VCE still there in
> *vecp upon entry to convert_vector_to_pointer_for_subscript, the difference
> between VIEW_CONVERT_EXPR and NON_LVALUE_EXPR is just that
> c_common_mark_addressable_vec looks through VCE and marks the inner part as
> addressable (because VCE is handled_component_p), while for non_lvalue_expr it
> does not.
>
> So, shall we convert_vector_to_pointer_for_subscript add something like
> if (!lvalue_p (*vecp))
> error_at (...); ?
> What wording for it?
I'd think it's reasonable to subscript a non-lvalue vector (including e.g.
the return value of a function with vector return type) - this might of
course need to create a temporary object, as with non-lvalue arrays.
next prev parent reply other threads:[~2014-11-18 16:55 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-06 17:53 [Bug middle-end/63764] New: nternal compiler error: " mkg at us dot ibm.com
2014-11-07 9:29 ` [Bug tree-optimization/63764] [5 Regression] ICE: " trippels at gcc dot gnu.org
2014-11-18 10:23 ` [Bug target/63764] " jakub at gcc dot gnu.org
2014-11-18 15:34 ` joseph at codesourcery dot com
2014-11-18 16:36 ` jakub at gcc dot gnu.org
2014-11-18 16:55 ` joseph at codesourcery dot com [this message]
2014-11-18 17:02 ` jakub at gcc dot gnu.org
2014-11-18 17:18 ` joseph at codesourcery dot com
2014-11-19 14:36 ` jakub at gcc dot gnu.org
2014-11-19 16:25 ` joseph at codesourcery dot com
2014-11-20 12:48 ` rguenth at gcc dot gnu.org
2014-11-21 9:26 ` jakub at gcc dot gnu.org
2014-11-21 9:35 ` jakub at gcc dot gnu.org
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