Re: c++/9524: ICE in c_expand_expr, at c-common.c:4319 whencompiling boost 1.29.0

[Michael Matz <matz at suse dot de>]

Hi,

reichelt@igpm.rwth-aachen.de writes:
> State-Changed-From-To: open->analyzed
> State-Changed-Why:
>     The code does indeed crash the compiler.
>     I bet this is the same failure as in PR 9443.
>     Just to be sure, however, I'm leaving the PR open.

A very reduced testcase for this error is:
-------- snip -------------
struct B {
  void (*f)(void);
  void g();
};
void B::g()
{
  B::f();
}
--------- snap ------------

This compiled with either 3.3 CVS or HEAD ICEs the compiler exhibits the
abort.  The causing patch for this is a big one from Mark, ChangeLog
starting with:

+2002-07-31  Mark Mitchell  <mark@codesourcery.com>
+
+       * call.c (build_field_call): Do not look up the field by name.
+       (build_method_call): Simplify.
+       (struct z_candidate): Add access_path and conversion_path.  Remove
+       basetype_path.
+       (convert_class_to_reference): Adjust use of
+       add_function_candidate.
+       (add_candidate): Add conversion_path argument.
....

When one removes the qualification from the call (i.e. replace 'B::f()'
with 'f()'), the file compiles.  The difference is, that while expanding
the call, in the working case it's a:
 <call_expr 0x40159d00
   ...
    arg 0 <component_ref 0x40159ce0
        type <pointer_type 0x40189e70 type <function_type 0x4015e2a0>
   ...

while in the broken case the call expressions is a:
 <call_expr 0x40159ce0
   ...
    arg 0 <field_decl 0x40189ee0 f
   ...

A field_decl is never expected as the first elem of a call_expr, and this
makes finally the expansion functions crash.


Ciao,
Michael.