Split out from PR23624.
For
template<int>
void f()
{
int *t, i;
t[i ? 0 : i];
}
the C++ frontend creates i ? 0 : i, i.e. an integer type conditional,
instead of i != 0 ? 0 : i in case of a template only. Causing this is
build_x_conditional_expr
...
expr = build_conditional_expr (ifexp, op1, op2);
if (processing_template_decl && expr != error_mark_node)
return build_min_non_dep (COND_EXPR, expr,
orig_ifexp, orig_op1, orig_op2);
where in the case of a template decl, the valid expr i != 0 ? 0 : i is
thrown away and rebuilt as i ? 0 : i, where the default conversion is no
longer applied. That could be fixed using perform_implicit_conversion
(boolean_type_node, orig_ifexp) - but I don't know if that would succeed
in case of i being a template param. We use this (potentially dependent)
expr later to create a non-dependent expr where we fail to apply the
default conversion, too, in
pt.c:build_non_dependent_expr
we could fix that there, too, performing default conversion if the type
is not correct. And later in
typeck.c:build_array_ref
we happen to call fold on the invalid(?) COND_EXPR.
patch:
http://gcc.gnu.org/ml/gcc-patches/2005-08/msg01740.html
--
Summary: C++ frontend passes invalid COND_EXPR to the middle-end
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rguenth at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23794
