------- Comment #3 from rguenth at gcc dot gnu dot org 2010-01-06 12:26 -------
Hm, I reduced it to something that is not a regression anymore. The original
testcase though works with 4.4 but fails with 4.5. I guess the real problem
is latent.
static inline __attribute__((always_inline)) int
__pskb_trim(void)
{
return ___pskb_trim();
}
static inline __attribute__((always_inline))
int pskb_trim(void)
{
return __pskb_trim();
}
int ___pskb_trim(void)
{
pskb_trim();
return 0;
}
Is rejected at -O2 but accepted at -O1. The issue is that we do not
compute always-inline inlines at once in one place but during early
inlining do
;; Function ___pskb_trim (___pskb_trim)
Considering to always inline inline candidate pskb_trim.
Not inlining: SSA form does not match.
;; Function __pskb_trim (__pskb_trim)
Considering inline candidate ___pskb_trim.
Inlining ___pskb_trim into __pskb_trim.
;; Function pskb_trim (pskb_trim)
Considering to always inline inline candidate __pskb_trim.
Inlining __pskb_trim into pskb_trim.
Considering to always inline inline candidate pskb_trim.
Not inlining: recursive call.
Inlining __pskb_trim to pskb_trim with frequency 1000
and with that particular oder of inlining (note especially how we
inline a non-always-inline function into an always-inline function!)
we end up with
pskb_trim ()
{
int D.1969;
int D.1969;
int D.1961;
<bb 2>:
pskb_trim ();
D.1969_5 = 0;
D.1961_1 = D.1969_5;
return D.1961_1;
}
which the IPA inliner complains about. At -O1 we do not perform the
bogus inlining during early inlining.
Now the cgraph has a very simple inlining solution:
int ___pskb_trim(void)
{
___pskb_trim();
return 0;
}
and we better produce that.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Component|regression |tree-optimization
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-01-06 12:26:10
date| |
Summary|unimplemented: inlining |[4.5 Regression]
|failed in call to |unimplemented: inlining
|‘pskb_trim’: recursive |failed in call to
|inlining |‘pskb_trim’: recursive
| |inlining
Target Milestone|--- |4.5.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42632
