[Bug ipa/60973] Invalid propagation of a tail call in devirt pass

["ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60973

--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Richard Biener from comment #1)

> Index: gcc/tree-inline.c

I have checked this patch on my target, where it fixes the runtime problem. The
optimized tree dump results in:

int main(int, char**) (int argc, char * * argv)
{
  int retval.0;
  struct C c;
  int _3;

  <bb 2>:
  C::C (&c);
  _3 = get_input ();
  retval.0_8 = C::foo (&c, _3);
  if (retval.0_8 != 4)
    goto <bb 3>;
  else
    goto <bb 4>;

  <bb 3>:
  abort ();

  <bb 4>:
  c ={v} {CLOBBER};
  return 0;

}

which expands to the correct RTL sequence.
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Subject: [Bug c++/61082] [x86-64 Itanium ABI] g++ uses wrong return location for class with head padding
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http://gcc.gnu.org/bugzilla/show_bug.cgi?ida082

--- Comment #14 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to David Greene from comment #13)
> I see that 3.2.3 4 (b) is talking about considering adjacent fields in an
> eightbyte.  Is the intent to classify each eightbyte in an aggregate and
> then consider each eightbyte separately for assigning argument and return
> registers?

That is correct.

> The post-merger cleanup described in 5 appears to handle passing in memory
> in that it considers all of the fields in the aggregate together.
>
> Given the above, if a field crosses an eightbyte either it is larger than an
> eightbyte either it is unaligned which forces the whole argument to memory
> or its eightbytes are classified separately in a recursive manner.
>
> Does this sound correct?  If so, I think gcc is correct in what it's doing.

I think GCC is correct.