https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93014
Bug ID: 93014
Summary: [9/10 Regression] ICE when initialising vector
references with -flax-vector-conversions
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Keywords: ice-on-invalid-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rsandifo at gcc dot gnu.org
Target Milestone: ---
This test:
typedef unsigned int v4si __attribute__ ((vector_size(16)));
typedef unsigned char v16qi __attribute__ ((vector_size(16)));
extern v16qi x;
v4si &y = x;
ICEs with:
a.c:4:11: internal compiler error: in convert_like_real, at cp/call.c:7670
This started with r260780, which had the effect of making lvalue_kind
look through VIEW_CONVERT_EXPR in all cases, not just for location
wrappers. This also means that:
typedef unsigned int v4si __attribute__ ((vector_size(16)));
typedef unsigned char v16qi __attribute__ ((vector_size(16)));
extern v16qi x;
v4si &y = reinterpret_cast<v4si>(x);
is now valid despite the result of the cast being an rvalue.
There might be two separate problems here:
(1) Vector conversions aren't being treated as rvalues when
they should be.
(2) The convert_like_real check seems to be trying (at least
partially) to reproduce the logic in reference_binding
that led to bad_p being set to true. But the "from" type
it's using is the result of the implicit conversion added
by reference_binding rather than the "from" type that
reference_binding was using. AFAICT he result of that
implicit converson should always be reference-compatible
with the reference type, so we don't get the error we
expected for that case.
