[Bug ipa/64164] New: [4.9/5 Regression] one more stack slot used due to one less inlining level

[Bug ipa/64164] New: [4.9/5 Regression] one more stack slot used due to one less inlining level

[patrick.marlier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

            Bug ID: 64164
           Summary: [4.9/5 Regression] one more stack slot used due to one
                    less inlining level
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: patrick.marlier at gmail dot com
              Host: x86_64-linux-gnu
            Target: x86_64-linux-gnu
             Build: x86_64-linux-gnu

Created attachment 34178
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34178&action=edit
testcase

$ cc -O2 -S -o stm.s stm.c
$ cc -O2 -DOPT -S -o stm-opt.s stm.c

if you compare the 2 outputs, stm_load function is using one more slot on the
stack.
The difference is only this:

static inline size_t
AO_myload2(const volatile size_t *addr)
{
  return *(size_t *)addr;
}
static inline size_t
AO_myload(const volatile size_t *addr)
{
#ifdef OPT
  size_t result = AO_myload2(addr);
#else
  size_t result = *(size_t *)addr;
#endif
  return result;
}

Having one more inlined function should have the same optimization not a better
one.
4.8 does not have the problem and the code generated is the same.

[Bug middle-end/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|ipa                         |middle-end

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Looks like out of SSA is producing the difference.
Change the function to just:
  return *(size_t *)addr;

Changes it to what the inline function does.

[Bug middle-end/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-12-03
     Ever confirmed|0                           |1

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
   Last reconfirmed|2014-12-03 00:00:00         |
          Component|middle-end                  |rtl-optimization
   Target Milestone|---                         |4.9.3

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
The difference is in whether there are extra user-named variables in the end
and thus SSA coalescing decision differences:

 stm_load (volatile stm_word_t * addr)
 {
-  stm_word_t l;
-  stm_word_t value;
   stm_word_t version;
   stm_word_t l;
   struct r_entry_t * r;
-  stm_word_t now;
...
+  size_t _32;
+  size_t _33;
+  size_t _34;

...

 Conflict graph:
+1: 3
+3: 1

 After sorting:
 Sorted Coalesce list:
+(16610) _30 <-> _33
 (651) _10 <-> _30

...

-Coalesce list: (10)_10 & (30)_30 [map: 1, 2] : Success -> 1
+Coalesce list: (30)_30 & (33)_33 [map: 2, 3] : Success -> 2
+Coalesce list: (10)_10 & (30)_30 [map: 1, 2] : Fail due to conflict


So it turns out the different coalescing ends up generating worse code.
It would be interesting to see why we decide that coalescing _30 and _33
is so much more beneficial than coalescing _10 and _30.

Ah, it simply uses EDGE_FREQUENCY...  and for some reason we predicted
that _33 & 1 != 0 is 10% taken only.

So ... the theory is that the version is faster on the important path?

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
That is, it is good

  # _30 = PHI <0(2), _10(8), value_33(7), value_33(3), value_33(6)>
  return _30;

vs bad

  # _30 = PHI <0(2), _10(8), _33(7), _33(3), _33(6)>
  return _30;

where it thinks that coalescing _30 and _33 is more important than
coalescing _30 and _10 (which looks reasonable).

The question is why RTL opts make such large difference out of this.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[patrick.marlier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #5 from Patrick Marlier <patrick.marlier at gmail dot com> ---
The regression starts from this commit:

trunk@200103
commit f82f0ea592c2d78077e03f5a1a3b9b40751cc116
Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Fri Jun 14 18:52:32 2013 +0000

        * gimple.h (gimple_can_coalesce_p): Prototype.
        * tree-ssa-coalesce.c (gimple_can_coalesce_p): New function.
        (create_outofssa_var_map, coalesce_partitions): Use it.
        * tree-ssa-uncprop.c (uncprop_into_successor_phis): Similarly.
        * tree-ssa-live.c (var_map_base_init): Use TYPE_CANONICAL
        if it's available.

        * gcc.dg/tree-ssa/coalesce-1.c: New test.

And especially from this:
gcc/tree-ssa-coalesce.c:gimple_can_coalesce_p (tree name1, tree name2)
...

  /* If the types are not the same, check for a canonical type match.  This
     (for example) allows coalescing when the types are fundamentally the
     same, but just have different names. 

     Note pointer types with different address spaces may have the same
     canonical type.  Those are rejected for coalescing by the
     types_compatible_p check.  */

  if (TYPE_CANONICAL (t1)
      && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2)
      && types_compatible_p (t1, t2))
    return true;

But as Richard mentioned, I think the problem is in the RTL part.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #7 from Jeffrey A. Law <law at redhat dot com> ---
OK, but why does this make such a difference in the final result.  Ie, what
happens as we get into RTL.

It would also be helpful to see the current & desired output for the case where
we've regressed.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[amacleod at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Andrew Macleod <amacleod at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |amacleod at redhat dot com

--- Comment #8 from Andrew Macleod <amacleod at redhat dot com> ---
(In reply to Alexandre Oliva from comment #6)

> 
> Coalescing SSA names even when neither has a root removes the optimization
> differences for this testcase.

I would worry about side effects... Coalescing is always a balancing act.   If
you allow things to coalesce when neither has a root, a few of those coalesced
together may prevent a coalesce with a much more desirable root in other
programs.  

And of course more coalesces may mean longer live ranges...  so any changes
like this need a lot of studying of side effects on a much larger set of
problems. 

It was a long time ago, so I don't remember the reasons, but most of these
kinds of restrictions were rooted in some kind of rationale... usually from
examining an issue of some sort and introducing the restriction to avoid it. 
The original conditions may no longer exist, but we'd have to run tests to make
sure nothing shows up.  Perhaps tweaking the costing model could help too.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #9 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #7)
> OK, but why does this make such a difference in the final result.  Ie, what happens as we get into RTL.

Err, I covered that bit in my description: we emit a number of copies, each
with a new BB of its own.  The additional pseudo survives all the way to the
end, and so do the copies, which is enough to explain the additional stack
slot.  Further rearrangement of code also follows from the additional blocks.

(In reply to Andrew Macleod from comment #8)
> most of these kinds of restrictions were rooted in some kind of rationale... usually from examining an issue of some sort and introducing the restriction to avoid it.

This one was added by https://gcc.gnu.org/ml/gcc-patches/2012-08/msg00517.html
The description mentions out-of-SSA coalescing, but not copyrename coalescing,
which is what this is about.  Since there were not anonymous SSA names before,
the introduced condition would necessarily not be met, so it effectively
reduced the amount of copyrename coalescing without any rationale AFAICT.

Richi, do you happen to have any insight as to why you changed copyrename to
avoid coalescing rootless ssa names?  Reverting it doesn't seem to have any ill
effects on code correctness (unlike allowing coalescing between rooted and
rootless vars during out-of-ssa, in gimple_can_coalesce_p, which breaks codegen
badly, though I haven't dug into why).  I'll attach a patch I'm testing to that
effect momentarily.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |aoliva at gcc dot gnu.org

--- Comment #10 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Created attachment 35048
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35048&action=edit
Patch that restores coalescing of anonymous SSA vars

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu.org

--- Comment #11 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Uhh, Richi, there's a question for you in comment 9, but I forgot to cc: you
before saving the post.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #12 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
I just noticed that I reversed with and without -DOPT in my analysis in comment
6.  Apologies for any confusion this may have caused.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #13 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
I looked further into why changing gimple_can_coalesce_p didn't work:
build_ssa_conflict_graph only marks conflicts between SSA names if they share
the same base variable.  This explains why we have a conflict in the conflict
map with -DOPT, in which l_4, values_29 and now_30 all have base variables,
whereas without -DOPT they don't.  So, we can't coalesce them with _10 and _28,
even though 10 and 29 do conflict.

I ran a test in which I allowed values_29 and _28 to coalesce, by hooking into
gimple_can_coalesce_p during an -UOPT out-of-ssa and getting it to return true.
 This yielded the same partition map as the -DOPT case, but an empty conflict
map for the reason above.  The sorted coalesce list was the same, too, so we
coalesced values_29 and _28, as in -DOPT, but then, due to the lack of the
conflict, we also coalesced _10 into the same partition.  This experimental
additional invalid coalescing in turn caused other differences in the generated
RTL.

At this point I'll sum up my findings:

- we fail to coalesce during copyrename because we've ruled out, at that point,
coalescing of anonymous SSA names.  as a consequence, only some coalescing
opportunities are taken, leaving some anonymous names that we try to coalesce
first not coalesced

- as a consequence, we fail to coalesce some SSA names because some of the SSA
variables have become anonymous whereas others aren't

- as a consequence, we emit additional copies in additional BBs, and they
survive all the way to the end of compilation

Although changing copyrename to allow coalescing in these cases fixes the
problem, I suppose it would also be possible to change out-of-ssa to
compensate; we would have to somehow mark conflicts between anonymous and
non-anonymous variables in the conflict graph, though.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #14 from Jeffrey A. Law <law at redhat dot com> ---
So, forgive me, but is -DOPT supposed to be the good or the bad code?

>From looking at the results I get, -DOPT is supposed to be the good code, but
that seems to conflict with c#6.

For -DOPT I get this PHI:

  # _28 = PHI <0(2), _29(3), _29(7), _10(8), _29(6)>

For -UOPT I get this:

  # _28 = PHI <0(2), value_29(3), value_29(7), _10(8), value_29(6)>


Note that _10 from BB 8 is known to have the value 0.  That equivalency comes
from the path 2->3->4->8.  Coalescing _10 with anything is probably the least
interesting.  Coalescing _28 and _29 seems more profitable.

Would we get better code if we left the constant in place?  Can we come up with
a reasonable heuristic to determine if we're better off with _10 or the
constant in that PHI argument?

Right now uncprop will always replace a constant with an SSA_NAME having the
right value if the SSA_NAME could potentially coalesce with the result of the
PHI.  The theory being that a constant will always need initialization, but if
the SSA_NAME coalesces with the result, then the SSA_NAME will likely be
"free".  The obvious exception is when that coalescing prevents other things
from coalescing.


I also wonder if we could be cleaning things up in RTL to make this less of an
issue.  For example, would optimizing the obvious tail-merge/crossjump earlier
in the RTL pipeline help the register allocator coalesce things better?

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Alexandre Oliva from comment #9)
> (In reply to Jeffrey A. Law from comment #7)
> > OK, but why does this make such a difference in the final result.  Ie, what happens as we get into RTL.
> 
> Err, I covered that bit in my description: we emit a number of copies, each
> with a new BB of its own.  The additional pseudo survives all the way to the
> end, and so do the copies, which is enough to explain the additional stack
> slot.  Further rearrangement of code also follows from the additional blocks.
> 
> (In reply to Andrew Macleod from comment #8)
> > most of these kinds of restrictions were rooted in some kind of rationale... usually from examining an issue of some sort and introducing the restriction to avoid it.
> 
> This one was added by
> https://gcc.gnu.org/ml/gcc-patches/2012-08/msg00517.html
> The description mentions out-of-SSA coalescing, but not copyrename
> coalescing, which is what this is about.  Since there were not anonymous SSA
> names before, the introduced condition would necessarily not be met, so it
> effectively reduced the amount of copyrename coalescing without any
> rationale AFAICT.
> 
> Richi, do you happen to have any insight as to why you changed copyrename to
> avoid coalescing rootless ssa names?

Because "coalescing" them doesn't do anything.  copyrename coalescing
assigns the same underlying DECL to SSA names, thus makes SSA_NAME_VAR
the same.  But when both SSA_NAME_VARs are NULL this won't do anything.

So the effect of the patch was rather that there are now way less SSA names
with SSA_NAME_VAR != NULL.  In particular all the pass created ones
(with no relation to user declared variables).  It didn't make sense to
apply copyrename to those (copyrename is to have better debug info in the end,
sth which should be provided by debug stmts today).

>  Reverting it doesn't seem to have any
> ill effects on code correctness (unlike allowing coalescing between rooted
> and rootless vars during out-of-ssa, in gimple_can_coalesce_p, which breaks
> codegen badly, though I haven't dug into why).  I'll attach a patch I'm
> testing to that effect momentarily.

So I'd say the patch can't make a difference - it at most can end up
re-writing the type of an SSA name and then having followup effects
in out-of-SSA coalescing?  For some odd reason we are ignoring some
type differences in copyrename coalescing.

But - how does either root1 or root2 end up non-zero at

  /* Set the root variable of the partition to the better choice, if there is
     one.  */
  if (!ign2 && root2)
    replace_ssa_name_symbol (partition_to_var (map, p3), root2);
  else if (!ign1 && root1) 
    replace_ssa_name_symbol (partition_to_var (map, p3), root1);
  else
    gcc_unreachable ();     

?  That is, the only effect of your patch is to do partiton_union?  Ah,
and then go to:

  /* Now one more pass to make all elements of a partition share the same
     root variable.  */

  for (x = 1; x < num_ssa_names; x++)
    {
      part_var = partition_to_var (map, x);
      if (!part_var)
        continue;
      var = ssa_name (x);
      if (SSA_NAME_VAR (var) == SSA_NAME_VAR (part_var))
        continue;
      if (debug)
        {
          fprintf (debug, "Coalesced ");
          print_generic_expr (debug, var, TDF_SLIM);
          fprintf (debug, " to ");
          print_generic_expr (debug, part_var, TDF_SLIM);
          fprintf (debug, "\n");
        }
      stats.coalesced++;
      replace_ssa_name_symbol (var, SSA_NAME_VAR (part_var));
    }

and wreck SSA names type (and "debug" identifier) only?  That really sounds
bogus.

The correct fix would be to allow the kind of type differences copyrename
coalescing allows also in out-of-SSA coalescing.

That is, I don't see how the patch makes sense.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
And as I analyzed in comment #3 we chose the now different coalescing because
it is more profitable (to the cost analysis we perform in out-of-SSA
coalescing).
So the fix, if any, is there (or in the code maintaining edge frequencies).

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> ---
To add to all this - IMHO copyrename should go - it's purpose was to have more
SSA names with user-decls and thus debug info for them.  This should now
be dealt with debug insns (in a way better and correct way).

Yes, out-of-SSA coalescing could be changed to allow coalescing of SSA names
with a user-DECL and anonymous SSA names (or SSA names with a DECL_IGNORED_P
decl).  But that will make the conflict graph much larger(?).  The decision
past
then was to retain previous behavior which wouldn't have coalesced this
case (because the DECL of the now anonymous SSA name was different).

In theory we could just go for it, hoping the conflict graph will not get
much larger.  But it might happen that we end up coalescing things in a way
that there ends up being no DECL for a register and thus we lose in debug
quality (not sure if we could compensate by inserting debug stmts on the
edges to compensate for that - we couldn't do that if it requires splitting
the edge).  Not sure if always coalescing to the variable with the user-decl
won't make debug info wrong, like in

  bb1:
  _1 = 2 * _3;
  goto <bb 3>;

  bb2:
  i_4 = 5 / _3;

  bb3:
  _3 = PHI <i_4 (2), _1  (1)>

if we coalesce to _1 to i_4 then the expression 2 * _3 will be computed
to a register with decl 'i'.

So to avoid wrong debug we'd have to always coalesce to an anonymous
entity - but that would lose the association of 'i' to 5 / _3 in bb2
unless we manage to compensate for that somehow with debug-insns we
magically emit during RTL expansion.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #18 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #14)
> So, forgive me, but is -DOPT supposed to be the good or the bad code?

It's the good one.  As noted in comment 12, I had that backwards in comment 6.

(In reply to Richard Biener from comment #15)
> Because "coalescing" them doesn't do anything.  copyrename coalescing
> assigns the same underlying DECL to SSA names, thus makes SSA_NAME_VAR
> the same.  But when both SSA_NAME_VARs are NULL this won't do anything.

This may be true when you look at only one pair of SSA names, but when you have
2 such candidate pairs involving one common SSA name, it can, and it does make
a difference, as described in comment 6.

(In reply to Richard Biener from comment #16)
> And as I analyzed in comment #3 we chose the now different coalescing because
> it is more profitable (to the cost analysis we perform in out-of-SSA
> coalescing).

No, we don't even *consider* the coalescing performed in the -DOPT case,
because, as noted in comment 13, the SSA names ended up with different base
names, because copyrename wouldn't give them the same base name.

(In reply to Richard Biener from comment #17)
> To add to all this - IMHO copyrename should go

That's fine with me.

> Yes, out-of-SSA coalescing could be changed to allow coalescing of SSA names
> with a user-DECL and anonymous SSA names (or SSA names with a DECL_IGNORED_P
> decl).  But that will make the conflict graph much larger(?).

Ok, I'll give that a shot tomorrow (I'll be away for the whole day today).

> might happen that we end up coalescing things in a way
> that there ends up being no DECL for a register and thus we lose in debug
> quality (not sure if we could compensate by inserting debug stmts on the
> edges to compensate for that - we couldn't do that if it requires splitting
> the edge).

I'm not concerned about that.  Any debug stmts needed to make this work will
already be in place, after the actual assignments, and after early PHI nodes. 
Sure, edge insertions might separate the copies from the debug stmts inserted
after the PHI nodes, but ultimately the bindings should take care of it.

> So to avoid wrong debug we'd have to always coalesce to an anonymous
> entity

With debug stmts, we don't care what the base names are any more.  All the info
we need (for tracked auto variables) is in the debug stmts.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #19 from rguenther at suse dot de <rguenther at suse dot de> ---
On Wed, 18 Mar 2015, aoliva at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
> 
> --- Comment #18 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
> (In reply to Jeffrey A. Law from comment #14)
> > So, forgive me, but is -DOPT supposed to be the good or the bad code?
> 
> It's the good one.  As noted in comment 12, I had that backwards in comment 6.
> 
> (In reply to Richard Biener from comment #15)
> > Because "coalescing" them doesn't do anything.  copyrename coalescing
> > assigns the same underlying DECL to SSA names, thus makes SSA_NAME_VAR
> > the same.  But when both SSA_NAME_VARs are NULL this won't do anything.
> 
> This may be true when you look at only one pair of SSA names, but when you have
> 2 such candidate pairs involving one common SSA name, it can, and it does make
> a difference, as described in comment 6.
> 
> (In reply to Richard Biener from comment #16)
> > And as I analyzed in comment #3 we chose the now different coalescing because
> > it is more profitable (to the cost analysis we perform in out-of-SSA
> > coalescing).
> 
> No, we don't even *consider* the coalescing performed in the -DOPT case,
> because, as noted in comment 13, the SSA names ended up with different base
> names, because copyrename wouldn't give them the same base name.
> 
> (In reply to Richard Biener from comment #17)
> > To add to all this - IMHO copyrename should go
> 
> That's fine with me.
> 
> > Yes, out-of-SSA coalescing could be changed to allow coalescing of SSA names
> > with a user-DECL and anonymous SSA names (or SSA names with a DECL_IGNORED_P
> > decl).  But that will make the conflict graph much larger(?).
> 
> Ok, I'll give that a shot tomorrow (I'll be away for the whole day today).
> 
> > might happen that we end up coalescing things in a way
> > that there ends up being no DECL for a register and thus we lose in debug
> > quality (not sure if we could compensate by inserting debug stmts on the
> > edges to compensate for that - we couldn't do that if it requires splitting
> > the edge).
> 
> I'm not concerned about that.  Any debug stmts needed to make this work will
> already be in place, after the actual assignments, and after early PHI nodes. 
> Sure, edge insertions might separate the copies from the debug stmts inserted
> after the PHI nodes, but ultimately the bindings should take care of it.
> 
> > So to avoid wrong debug we'd have to always coalesce to an anonymous
> > entity
> 
> With debug stmts, we don't care what the base names are any more.  All the info
> we need (for tracked auto variables) is in the debug stmts.

But we do not always have debug stmts!

int bar (int b)
{
  int i;
  if (b > 7)
    i = b / 3;
  else
    return b * 4;
  return i;
}

is a testcase for what I am thinking of.  Hmm.  For some reason
into-SSA inserts a debug stmt, creating an extra copy _5 = i_4?!

  <bb 2>:
  if (b_2(D) > 7)
    goto <bb 3>;
  else
    goto <bb 4>;

  <bb 3>:
  i_4 = b_2(D) / 3;
  # DEBUG i => i_4
  _5 = i_4;
  goto <bb 5>;

  <bb 4>:
  _3 = b_2(D) * 4;

  <bb 5>:
  # _1 = PHI <_3(4), _5(3)>

so indeed we shouldn't lose anything here.  But are you sure
that we are never using REG_EXPR for debug?  With 
-fno-var-tracking-assignments for sure we do (I suppose we don't care),
at least var-tracking.c does look at REG_EXPR.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #20 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
(In reply to Alexandre Oliva from comment #18)
> No, we don't even *consider* the coalescing performed in the -DOPT case,
> because, as noted in comment 13, the SSA names ended up with different base
> names, because copyrename wouldn't give them the same base name.
> 
> (In reply to Richard Biener from comment #17)
> > To add to all this - IMHO copyrename should go
> 
> That's fine with me.
> 
> > Yes, out-of-SSA coalescing could be changed to allow coalescing of SSA names
> > with a user-DECL and anonymous SSA names (or SSA names with a DECL_IGNORED_P
> > decl).  But that will make the conflict graph much larger(?).

Not only that: unless we allow also coalescing between different SSA names in
out-of-ssa, we'll lose optimizations that copyrename would have enabled
out-of-SSA to make, because the removed copyrename won't have assigned the same
base name to otherwise unrelated SSA names that out-of-SSA won't even consider
for coalescing.  Now *this* might make the conflict graph explode in size.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #21 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #19)
> For some reason
> into-SSA inserts a debug stmt, creating an extra copy _5 = i_4?!

I bet the extra copy is there even without -g.  _1, _3 and _5 seem to be SSA
names for the result decl.  Presumably _5 might be optimized out, replaced with
i_4 in the _1 PHI node, at a later pass.

> But are you sure
> that we are never using REG_EXPR for debug?

We use them for non-gimple_register auto variables.

> With 
> -fno-var-tracking-assignments for sure we do (I suppose we don't care),

Yeah, I'd say we don't care.  If one asks for debug info degradation, we obey
;-)
(now, sometimes we disable VTA on our own because some internal limit is
exceeded; that's unfortunate, but what are you gonna do? :-)

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #22 from Jeffrey A. Law <law at redhat dot com> ---
Let's try to stay focused.  Killing copyrename seems like a fine thing to do as
long as the resulting debug info is good.  But that's independent of this BZ.

I still find myself wondering if leaving the "0" instead of "_10" in that PHI
node is a reasonable approach.  Certainly if I hack uncprop to leave things in
that state, I get the code we want.

And ISTM that uncprop ought to leave the constant alone if the SSA_NAME holding
the constant conflicts with any of the other SSA_NAMEs in the PHI node that may
potentially coalesce with the PHI result.  That captures pretty well the case
where the constant is better than an SSA_NAME.

In this particular case, we have:

  # _28 = PHI <0(2), _29(3), _29(7), _10(8), _29(6)>

When _28 and _10 coalesce, the result then conflicts with _29 during IRA/LRA
because of the extended lifetime of _10).  Thus the annoying copies created by
out-of-ssa can't be eliminated.

WIth the proposed change, we'd instead have:

  # _28 = PHI <0(2), _29(3), _29(7), 0(8), _29(6)>

While we won't coalesce _28/_29 during out-of-ssa, LRA will see the copies and
note that the associated pseudos don't conflict and ultimately assign them to
the same hard register and the annoying copies are gone.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #23 from rguenther at suse dot de <rguenther at suse dot de> ---
On Fri, 20 Mar 2015, law at redhat dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
> 
> --- Comment #22 from Jeffrey A. Law <law at redhat dot com> ---
> Let's try to stay focused.  Killing copyrename seems like a fine thing to do as
> long as the resulting debug info is good.  But that's independent of this BZ.
> 
> I still find myself wondering if leaving the "0" instead of "_10" in that PHI
> node is a reasonable approach.  Certainly if I hack uncprop to leave things in
> that state, I get the code we want.
> 
> And ISTM that uncprop ought to leave the constant alone if the SSA_NAME holding
> the constant conflicts with any of the other SSA_NAMEs in the PHI node that may
> potentially coalesce with the PHI result.  That captures pretty well the case
> where the constant is better than an SSA_NAME.
> 
> In this particular case, we have:
> 
>   # _28 = PHI <0(2), _29(3), _29(7), _10(8), _29(6)>
> 
> When _28 and _10 coalesce, the result then conflicts with _29 during IRA/LRA
> because of the extended lifetime of _10).  Thus the annoying copies created by
> out-of-ssa can't be eliminated.
> 
> WIth the proposed change, we'd instead have:
> 
>   # _28 = PHI <0(2), _29(3), _29(7), 0(8), _29(6)>
> 
> While we won't coalesce _28/_29 during out-of-ssa, LRA will see the copies and
> note that the associated pseudos don't conflict and ultimately assign them to
> the same hard register and the annoying copies are gone.

Sure - but then we'd better integrate uncprop into the coalescing,
otherwise you need to re-compute conflicts / live twice.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #24 from Jeffrey A. Law <law at redhat dot com> ---
Integrating uncprop and out-of-ssa certainly crossed my mind when I wrote that
comment :-)  Or at least arranging to build the life info/conflict stuff once
and have it shared.

A poor man's version is to note the path for the equivalence and see if any of
the blocks on that path define the other PHI arguments.  That ought to be fast
and simple enough to possibly include in gcc5.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #25 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
WIP patch accidentally posted to gcc-patches:
https://gcc.gnu.org/ml/gcc-patches/2015-03/msg01460.html

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #26 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Patch posted at https://gcc.gnu.org/ml/gcc-patches/2015-03/msg01491.html

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[patrick.marlier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #27 from Patrick Marlier <patrick.marlier at gmail dot com> ---
I confirm that the patch fixes the performance problem that I had. I guess the
patch is too complex to be backported.

Thanks a lot Alexandre for the patch and to all for the deep analysis!
(just waiting for review and commit :))

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #28 from Jeffrey A. Law <law at redhat dot com> ---
So I've been thinking about how to integrate life/conflict analysis into the
uncprop code and it may not be that bad, both from an implementation and
computation standpoint.

Most importantly, we don't have to compute full life information.  We really
just need to compute the life of the equivalence.  Given the life of the
equivalence, if the equivalence is live in any block that contains the defining
statement for an SSA_NAME appearing in the target PHI, then the equivalence
conflicts and we don't want to unpropagate it.

Computing the life of the equivalence is pretty easy and should be reasonably
quick.  This is a cost we'd have to pay regardless of whether or not we
integrate uncprop with out-of-ssa since we won't have life information for the
expression.

Collecting the SSA_NAMEs appearing on the RHS of the PHI so that we don't test
for conflicts multiple times if an SSA_NAME shows up in multiple PHI
alternatives would help keep the cost down as well.

Ultimately I don't think we need to integrate uncprop and out-of-ssa to avoid
the unprofitable transformation during uncprop.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #29 from Jeffrey A. Law <law at redhat dot com> ---
No decision has been made on whether or not to include either or both
approaches to fixing this BZ into GCC 5.  It's still under evaluation/review. 
I think for GCC 6 it's highly likely we'll have both since they're both
independently good things to do.

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #30 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #28)
> So I've been thinking about how to integrate life/conflict analysis into the
> uncprop code and it may not be that bad, both from an implementation and
> computation standpoint.
> 
> Most importantly, we don't have to compute full life information.  We really
> just need to compute the life of the equivalence.  Given the life of the
> equivalence, if the equivalence is live in any block that contains the
> defining statement for an SSA_NAME appearing in the target PHI, then the
> equivalence conflicts and we don't want to unpropagate it.
> 
> Computing the life of the equivalence is pretty easy and should be
> reasonably quick.  This is a cost we'd have to pay regardless of whether or
> not we integrate uncprop with out-of-ssa since we won't have life
> information for the expression.
> 
> Collecting the SSA_NAMEs appearing on the RHS of the PHI so that we don't
> test for conflicts multiple times if an SSA_NAME shows up in multiple PHI
> alternatives would help keep the cost down as well.
> 
> Ultimately I don't think we need to integrate uncprop and out-of-ssa to
> avoid the unprofitable transformation during uncprop.

Also see "Boissinot et al., Fast Liveness Checking for SSA-Form Programs"
(CGO 08).  They describe a way to do fast liveness queries without actually
doing a (memory) expensive data-flow analysis but using SSA immediate-uses
and dominance checks.  Sth we could use in SSA coalescing as well to avoid
both the liveness bitmaps and the conflict graph.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.9.3                       |6.0
            Summary|[4.9/5 Regression] one more |[4.9/5/6 Regression] one
                   |stack slot used due to one  |more stack slot used due to
                   |less inlining level         |one less inlining level
      Known to fail|                            |5.0

--- Comment #31 from Richard Biener <rguenth at gcc dot gnu.org> ---
I'd say we push this back to GCC 6.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #32 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Agreed, though ideally it should be fixed early in stage1.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #34 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #33)
> On 03/31/2015 05:25 AM, rguenth at gcc dot gnu.org wrote:
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
> >
> > --- Comment #30 from Richard Biener <rguenth at gcc dot gnu.org> ---
> > (In reply to Jeffrey A. Law from comment #28)
> >> So I've been thinking about how to integrate life/conflict analysis into the
> >> uncprop code and it may not be that bad, both from an implementation and
> >> computation standpoint.
> >>
> >> Most importantly, we don't have to compute full life information.  We really
> >> just need to compute the life of the equivalence.  Given the life of the
> >> equivalence, if the equivalence is live in any block that contains the
> >> defining statement for an SSA_NAME appearing in the target PHI, then the
> >> equivalence conflicts and we don't want to unpropagate it.
> >>
> >> Computing the life of the equivalence is pretty easy and should be
> >> reasonably quick.  This is a cost we'd have to pay regardless of whether or
> >> not we integrate uncprop with out-of-ssa since we won't have life
> >> information for the expression.
> >>
> >> Collecting the SSA_NAMEs appearing on the RHS of the PHI so that we don't
> >> test for conflicts multiple times if an SSA_NAME shows up in multiple PHI
> >> alternatives would help keep the cost down as well.
> >>
> >> Ultimately I don't think we need to integrate uncprop and out-of-ssa to
> >> avoid the unprofitable transformation during uncprop.
> >
> > Also see "Boissinot et al., Fast Liveness Checking for SSA-Form Programs"
> > (CGO 08).  They describe a way to do fast liveness queries without actually
> > doing a (memory) expensive data-flow analysis but using SSA immediate-uses
> > and dominance checks.  Sth we could use in SSA coalescing as well to avoid
> > both the liveness bitmaps and the conflict graph.
> Yea, it looks reasonably interesting and there's probably benefit in 
> experimenting with that approach.  However, be aware that it's memory 
> consumption can be problematical.   According to their summary, it's 
> quadratic.

Yes, but that's only if you store the liveness info.  We don't need to do that
but we only need to compute whether two partitions conflict for each coalescing
candidate (which means a few SSA conflict checks dependent on partition size).

Our current algorithm is already quadratic in memory use because we do
store SSA liveness and the partition conflict graph.

What I'm not sure is whether doing the SSA based liveness check is going to
be slower compile-time wise.

>  Though presumably we could drop back to the tried and true 
> approach if we have too many BBs.
> 
> That definitely is stage1 material.

Indeed.

> Jeff

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #35 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Tue Jun  9 05:05:34 2015
New Revision: 224262

URL: https://gcc.gnu.org/viewcvs?rev=224262&root=gcc&view=rev
Log:
[PR64164] Drop copyrename, use coalescible partition as base when optimizing.

for  gcc/ChangeLog

        PR rtl-optimization/64164
        * Makefile.in (OBJS): Drop tree-ssa-copyrename.o.
        * tree-ssa-copyrename.c: Removed.
        * opts.c (default_options_table): Drop -ftree-copyrename.  Add
        -ftree-coalesce-vars.
        * passes.def: Drop all occurrences of pass_rename_ssa_copies.
        * common.opt (ftree-copyrename): Ignore.
        (ftree-coalesce-inlined-vars): Likewise.
        * doc/invoke.texi: Remove the ignored options above.
        * gimple-expr.h (gimple_can_coalesce_p): Move declaration
        * tree-ssa-coalesce.h: ... here.
        * tree-ssa-uncprop.c: Include tree-ssa-coalesce.h and other
        headers required by it.
        * gimple-expr.c (gimple_can_coalesce_p): Allow coalescing
        across variables when flag_tree_coalesce_vars.  Check register
        use and promoted modes to allow coalescing.  Moved to
        tree-ssa-coalesce.c.
        * tree-ssa-live.c (struct tree_int_map_hasher): Move along
        with its member functions to tree-ssa-coalesce.c.
        (var_map_base_init): Likewise.  Renamed to
        compute_samebase_partition_bases.
        (partition_view_normal): Drop want_bases parameter.
        (partition_view_bitmap): Likewise.
        * tree-ssa-live.h: Adjust declarations.
        * tree-ssa-coalesce.c: Include explow.h.
        (build_ssa_conflict_graph): Process PARM_ and RESULT_DECLs's
        default defs at the entry point.
        (dump_part_var_map): New.
        (compute_optimized_partition_bases): New, called by...
        (coalesce_ssa_name): ... when flag_tree_coalesce_vars, instead
        of compute_samebase_partition_bases.  Adjust.
        * alias.c (nonoverlapping_memrefs_p): Disregard gimple-regs.
        * cfgexpand.c (leader_merge): New.
        (get_rtl_for_parm_ssa_default_def): New.
        (set_rtl): Merge exprs and attrs, even for MEMs and non-SSA
        vars.  Update DECL_RTL for PARM_DECLs and RESULT_DECLs too.
        (expand_one_stack_var_at): Handle anonymous SSA_NAMEs.  Drop
        redundant MEM attr setting.
        (expand_one_stack_var_1): Handle anonymous SSA_NAMEs.  Renamed
        from...
        (expand_one_stack_var): ... this.  New wrapper to check and
        skip already expanded SSA partitions.
        (record_alignment_for_reg_var): New, factored out of...
        (expand_one_var): ... this.
        (expand_one_ssa_partition): New.
        (adjust_one_expanded_partition_var): New.
        (expand_one_register_var): Check and skip already expanded SSA
        partitions.
        (expand_used_vars): Don't create DECLs for anonymous SSA
        names.  Expand all SSA partitions, then adjust all SSA names.
        (pass::execute): Replace the loops that set
        SA.partition_to_pseudo from partition leaders and cleared
        DECL_RTL for multi-location variables, and that which used to
        rename vars and set attrs, with one that clears DECL_RTL and
        checks that PARMs and RESULTs default_defs match DECL_RTL.
        * cfgexpand.h (get_rtl_for_parm_ssa_default_def): Declare.
        * emit-rtl.c (set_reg_attrs_for_parm): Handle NULL decl.
        * explow.c (promote_ssa_mode): New.
        * explow.h (promote_ssa_mode): Declare.
        * expr.c (expand_expr_real_1): Handle anonymous SSA_NAMEs.
        * function.c: Include cfgexpand.h.
        (use_register_for_decl): Handle SSA_NAMEs, anonymous or not.
        (use_register_for_parm_decl): Wrapper for the above to
        special-case the result_ptr.
        (rtl_for_parm): Ditto for get_rtl_for_parm_ssa_default_def.
        (maybe_reset_rtl_for_parm): Reset DECL_RTL of parms with
        multiple locations.
        (assign_parm_adjust_stack_rtl): Add all and parm arguments,
        for rtl_for_parm.  For SSA-assigned parms, zero stack_parm.
        (assign_parm_setup_block): Prefer SSA-assigned location.
        (assign_parm_setup_reg): Likewise.  Use entry_parm for equiv
        if stack_parm is NULL.
        (assign_parm_setup_stack): Prefer SSA-assigned location.
        (assign_parms): Maybe reset DECL_RTL of params.  Adjust stack
        rtl before testing for pointer bounds.  Special-case result_ptr.
        (expand_function_start): Maybe reset DECL_RTL of result.
        Prefer SSA-assigned location for result and static chain.
        Factor out DECL_RESULT and SET_DECL_RTL.
        * tree-outof-ssa.c (insert_value_copy_on_edge): Handle
        anonymous SSA names.  Use promote_ssa_mode.
        (get_temp_reg): Likewise.
        (remove_ssa_form): Adjust.
        * var-tracking.c (dataflow_set_clear_at_call): Take call_insn
        and get its reg_usage for reg invalidation.
        (compute_bb_dataflow): Pass it insn.
        (emit_notes_in_bb): Likewise.
        * tree-ssa-loop-niter.c (loop_exits_before_overflow): Don't
        fail assert on conversion between unsigned types.

for  gcc/testsuite/ChangeLog

        * gcc.dg/guality/pr54200.c: Add -fno-tree-coalesce-vars.
        * gcc.dg/ssp-1.c: Make counter a register.
        * gcc.dg/ssp-2.c: Likewise.
        * gcc.dg/torture/parm-coalesce.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/parm-coalesce.c
Removed:
    trunk/gcc/tree-ssa-copyrename.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/Makefile.in
    trunk/gcc/alias.c
    trunk/gcc/cfgexpand.c
    trunk/gcc/cfgexpand.h
    trunk/gcc/common.opt
    trunk/gcc/doc/invoke.texi
    trunk/gcc/emit-rtl.c
    trunk/gcc/explow.c
    trunk/gcc/explow.h
    trunk/gcc/expr.c
    trunk/gcc/function.c
    trunk/gcc/gimple-expr.c
    trunk/gcc/gimple-expr.h
    trunk/gcc/opts.c
    trunk/gcc/passes.def
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/guality/pr54200.c
    trunk/gcc/testsuite/gcc.dg/ssp-1.c
    trunk/gcc/testsuite/gcc.dg/ssp-2.c
    trunk/gcc/tree-outof-ssa.c
    trunk/gcc/tree-ssa-coalesce.c
    trunk/gcc/tree-ssa-coalesce.h
    trunk/gcc/tree-ssa-live.c
    trunk/gcc/tree-ssa-live.h
    trunk/gcc/tree-ssa-loop-niter.c
    trunk/gcc/tree-ssa-uncprop.c
    trunk/gcc/var-tracking.c

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
            Summary|[4.9/5/6 Regression] one    |[4.9/5 Regression] one more
                   |more stack slot used due to |stack slot used due to one
                   |one less inlining level     |less inlining level

--- Comment #36 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
I don't think we're backporting this huge change, and the much smaller one
wasn't well-received, so...

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ebotcazou at gcc dot gnu.org

--- Comment #37 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
The patch severely breaks on SPARC though:

int foo (char c)
{
  return (int) c;
}

eric@polaris:~/build/gcc/sparc-sun-solaris2.10> gcc/xgcc -Bgcc -S -O t.c
t.c: In function 'foo':
t.c:1:5: internal compiler error: in assign_parm_setup_reg, at function.c:3120
 int foo (char c)
     ^
0xa335d0 assign_parm_setup_reg
        /home/eric/svn/gcc/gcc/function.c:3120
0xa3660f assign_parms
        /home/eric/svn/gcc/gcc/function.c:3778
0xa3a9fd expand_function_start(tree_node*)
        /home/eric/svn/gcc/gcc/function.c:5215
0x838716 execute
        /home/eric/svn/gcc/gcc/cfgexpand.c:6127
Please submit a full bug report,

[Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

David Edelsohn <dje at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dje at gcc dot gnu.org

--- Comment #38 from David Edelsohn <dje at gcc dot gnu.org> ---
It also broke ARM and PowerPC.  This patch should have been tested on all of
the config-list.mk targets.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |ASSIGNED
         Resolution|FIXED                       |---
            Summary|[4.9/5 Regression] one more |[4.9/5/6 Regression] one
                   |stack slot used due to one  |more stack slot used due to
                   |less inlining level         |one less inlining level

--- Comment #39 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
At least the sparc regression was caused by the change richi requested to
disregard the underlying decl in promote_ssa_mode.  I didn't realize this could
cause a mismatch between the mode of the partition created for the QImode parm
default def and the promoted mode for the parm decl expected by the
parm-assignment code in function.c.  This will likely take some time to sort
out, so I'm reverting the patch for now.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[clyon at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Christophe Lyon <clyon at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clyon at gcc dot gnu.org

--- Comment #40 from Christophe Lyon <clyon at gcc dot gnu.org> ---
Created attachment 35740
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35740&action=edit
ARM testcase

This is the testcase that breaks on ARM, when compiled with optimizations: -O0
is OK, -O1, -O2, -O3 crash with:
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/libgcc/fixed-bit.c:
In function '__gnu_addqq3':
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/libgcc/fixed-bit.c:59:1:
internal compiler error: RTL flag check: MEM_VOLATILE_P used with unexpected
rtx code 'reg' in set_mem_attributes_minus_bitpos, at emit-rtl.c:1787
 FIXED_ADD (FIXED_C_TYPE a, FIXED_C_TYPE b)
 ^
0xa6eb52 rtl_check_failed_flag(char const*, rtx_def const*, char const*, int,
char const*)
       
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/gcc/rtl.c:800
0x771fc7 set_mem_attributes_minus_bitpos(rtx_def*, tree_node*, int, long)
       
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/gcc/emit-rtl.c:1787
0x805294 assign_parm_setup_block
       
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/gcc/function.c:2977
0x80b65c assign_parms
       
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/gcc/function.c:3775
0x80e087 expand_function_start(tree_node*)
       
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/gcc/function.c:5215
0x6a77ed execute
       
/media/lyon/9be1a707-5b7f-46da-9106-e084a5dbb011/ssd/src/GCC/sources/gcc-fsf/trunk/gcc/cfgexpand.c:6127
Please submit a full bug report,

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #41 from David Edelsohn <dje at gcc dot gnu.org> ---
Created attachment 35742
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35742&action=edit
AIX PowerPC testcase

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #42 from David Edelsohn <dje at gcc dot gnu.org> ---
Created attachment 35743
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35743&action=edit
PPC64LE Linux Testcase

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #43 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Thu Jul 23 15:34:49 2015
New Revision: 226113

URL: https://gcc.gnu.org/viewcvs?rev=226113&root=gcc&view=rev
Log:
[PR64164] Drop copyrename, use coalescible partition as base when optimizing.

for  gcc/ChangeLog

        PR rtl-optimization/64164
        * Makefile.in (OBJS): Drop tree-ssa-copyrename.o.
        * tree-ssa-copyrename.c: Removed.
        * opts.c (default_options_table): Drop -ftree-copyrename.  Add
        -ftree-coalesce-vars.
        * passes.def: Drop all occurrences of pass_rename_ssa_copies.
        * common.opt (ftree-copyrename): Ignore.
        (ftree-coalesce-inlined-vars): Likewise.
        * doc/invoke.texi: Remove the ignored options above.
        * gimple-expr.h (gimple_can_coalesce_p): Move declaration
        * tree-ssa-coalesce.h: ... here.
        * tree-ssa-uncprop.c: Include tree-ssa-coalesce.h and other
        headers required by it.
        * gimple-expr.c (gimple_can_coalesce_p): Allow coalescing
        across variables when flag_tree_coalesce_vars.  Check register
        use and promoted modes to allow coalescing.  Moved to
        tree-ssa-coalesce.c.
        * tree-ssa-live.c (struct tree_int_map_hasher): Move along
        with its member functions to tree-ssa-coalesce.c.
        (var_map_base_init): Likewise.  Renamed to
        compute_samebase_partition_bases.
        (partition_view_normal): Drop want_bases parameter.
        (partition_view_bitmap): Likewise.
        * tree-ssa-live.h: Adjust declarations.
        * tree-ssa-coalesce.c: Include explow.h.
        (build_ssa_conflict_graph): Process PARM_ and RESULT_DECLs's
        default defs at the entry point.
        (dump_part_var_map): New.
        (compute_optimized_partition_bases): New, called by...
        (coalesce_ssa_name): ... when flag_tree_coalesce_vars, instead
        of compute_samebase_partition_bases.  Adjust.
        * alias.c (nonoverlapping_memrefs_p): Disregard gimple-regs.
        * cfgexpand.c (leader_merge): New.
        (get_rtl_for_parm_ssa_default_def): New.
        (set_rtl): Merge exprs and attrs, even for MEMs and non-SSA
        vars.  Update DECL_RTL for PARM_DECLs and RESULT_DECLs too.
        (expand_one_stack_var_at): Handle anonymous SSA_NAMEs.  Drop
        redundant MEM attr setting.
        (expand_one_stack_var_1): Handle anonymous SSA_NAMEs.  Renamed
        from...
        (expand_one_stack_var): ... this.  New wrapper to check and
        skip already expanded SSA partitions.
        (record_alignment_for_reg_var): New, factored out of...
        (expand_one_var): ... this.
        (expand_one_ssa_partition): New.
        (adjust_one_expanded_partition_var): New.
        (expand_one_register_var): Check and skip already expanded SSA
        partitions.
        (expand_used_vars): Don't create DECLs for anonymous SSA
        names.  Expand all SSA partitions, then adjust all SSA names.
        (pass::execute): Replace the loops that set
        SA.partition_to_pseudo from partition leaders and cleared
        DECL_RTL for multi-location variables, and that which used to
        rename vars and set attrs, with one that clears DECL_RTL and
        checks that PARMs and RESULTs default_defs match DECL_RTL.
        * cfgexpand.h (get_rtl_for_parm_ssa_default_def): Declare.
        * emit-rtl.c (set_reg_attrs_for_parm): Handle NULL decl.
        * explow.c (promote_ssa_mode): New.
        * explow.h (promote_ssa_mode): Declare.
        * expr.c (expand_expr_real_1): Handle anonymous SSA_NAMEs.
        * function.c: Include cfgexpand.h.
        (use_register_for_decl): Handle SSA_NAMEs, anonymous or not.
        (use_register_for_parm_decl): Wrapper for the above to
        special-case the result_ptr.
        (rtl_for_parm): Ditto for get_rtl_for_parm_ssa_default_def.
        (split_complex_args): Take assign_parm_data_all argument.
        Pass it to rtl_for_parm.  Set up rtl and context for split
        args.
        (assign_parms_augmented_arg_list): Adjust.
        (maybe_reset_rtl_for_parm): Reset DECL_RTL of parms with
        multiple locations.  Recognize split complex args.
        (assign_parm_adjust_stack_rtl): Add all and parm arguments,
        for rtl_for_parm.  For SSA-assigned parms, zero stack_parm.
        (assign_parm_setup_block): Prefer SSA-assigned location.
        (assign_parm_setup_reg): Likewise.  Use entry_parm for equiv
        if stack_parm is NULL.
        (assign_parm_setup_stack): Prefer SSA-assigned location.
        (assign_parms): Maybe reset DECL_RTL of params.  Adjust stack
        rtl before testing for pointer bounds.  Special-case result_ptr.
        (expand_function_start): Maybe reset DECL_RTL of result.
        Prefer SSA-assigned location for result and static chain.
        Factor out DECL_RESULT and SET_DECL_RTL.
        * tree-outof-ssa.c (insert_value_copy_on_edge): Handle
        anonymous SSA names.  Use promote_ssa_mode.
        (get_temp_reg): Likewise.
        (remove_ssa_form): Adjust.
        * stor-layout.c (layout_decl): Don't set mem attributes of
        non-MEMs.
        * var-tracking.c (dataflow_set_clear_at_call): Take call_insn
        and get its reg_usage for reg invalidation.
        (compute_bb_dataflow): Pass it insn.
        (emit_notes_in_bb): Likewise.

for  gcc/testsuite/ChangeLog

        * gcc.dg/guality/pr54200.c: Add -fno-tree-coalesce-vars.
        * gcc.dg/ssp-1.c: Make counter a register.
        * gcc.dg/ssp-2.c: Likewise.
        * gcc.dg/torture/parm-coalesce.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/parm-coalesce.c
Removed:
    trunk/gcc/tree-ssa-copyrename.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/Makefile.in
    trunk/gcc/alias.c
    trunk/gcc/cfgexpand.c
    trunk/gcc/cfgexpand.h
    trunk/gcc/common.opt
    trunk/gcc/doc/invoke.texi
    trunk/gcc/emit-rtl.c
    trunk/gcc/explow.c
    trunk/gcc/explow.h
    trunk/gcc/expr.c
    trunk/gcc/function.c
    trunk/gcc/gimple-expr.c
    trunk/gcc/gimple-expr.h
    trunk/gcc/opts.c
    trunk/gcc/passes.def
    trunk/gcc/stor-layout.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/guality/pr54200.c
    trunk/gcc/testsuite/gcc.dg/ssp-1.c
    trunk/gcc/testsuite/gcc.dg/ssp-2.c
    trunk/gcc/tree-outof-ssa.c
    trunk/gcc/tree-ssa-coalesce.c
    trunk/gcc/tree-ssa-coalesce.h
    trunk/gcc/tree-ssa-live.c
    trunk/gcc/tree-ssa-live.h
    trunk/gcc/tree-ssa-uncprop.c
    trunk/gcc/var-tracking.c

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #44 from Andreas Schwab <schwab@linux-m68k.org> ---
This breaks gcc.dg/pr43300.c on aarch64.

$ gcc/xgcc -B gcc/ ../gcc/testsuite/gcc.dg/pr43300.c
../gcc/testsuite/gcc.dg/pr43300.c: In function ‘foo’:
../gcc/testsuite/gcc.dg/pr43300.c:8:1: internal compiler error: in
emit_move_insn, at expr.c:3552
 foo (int x, V2SF a)
 ^
0x7ee783 emit_move_insn(rtx_def*, rtx_def*)
        ../../gcc/expr.c:3551
0x84a80b assign_parm_setup_reg
        ../../gcc/function.c:3322
0x84c4ff assign_parms
        ../../gcc/function.c:3766
0x84f353 expand_function_start(tree_node*)
        ../../gcc/function.c:5192
0x6f919f execute
        ../../gcc/cfgexpand.c:6105
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Subject: [Bug plugins/66991] New: GCCPLUGIN_VERSION_MAJOR == 5 & GCCPLUGIN_VERSION_MINOR == 5 for GCC 5.5.1
Date: Fri, 24 Jul 2015 10:42:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf991

            Bug ID: 66991
           Summary: GCCPLUGIN_VERSION_MAJOR == 5 & GCCPLUGIN_VERSION_MINOR
                    == 5 for GCC 5.5.1
           Product: gcc
           Version: 5.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: plugins
          Assignee: unassigned at gcc dot gnu.org
          Reporter: basile at starynkevitch dot net
  Target Milestone: ---

At least on my GNU/Linux/Debian/x86-64/Unstable the
/usr/lib/gcc/x86_64-linux-gnu/5/plugin/include/plugin-version.h file from
package gcc-5-plugin-dev version 5.1.1-14  contains incorrectly the following
lines:

#define GCCPLUGIN_VERSION_MAJOR   5
#define GCCPLUGIN_VERSION_MINOR   5
#define GCCPLUGIN_VERSION_PATCHLEVEL   5
#define GCCPLUGIN_VERSION  (GCCPLUGIN_VERSION_MAJOR*1000 +
GCCPLUGIN_VERSION_MINOR)

The GCCPLUGIN_VERSION_MINOR & GCCPLUGIN_VERSION_PATCHLEVEL are both incorrect.
They should be 1 & 1 respectively.

(It could be a Debian specific bug, but I don't think so. This file is
generated at GCC build time).

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #45 from Andreas Schwab <schwab@linux-m68k.org> ---
It also breaks a lot of tests on m68k, eg:

$ gcc/xgcc -B gcc/ ../gcc/testsuite/gcc.dg/pr17957.c 
../gcc/testsuite/gcc.dg/pr17957.c: In function ‘vadd’:
../gcc/testsuite/gcc.dg/pr17957.c:6:1: internal compiler error: in
expand_one_stack_var_1, at cfgexpand.c:1221
 vadd (void)
 ^
0x662055 expand_one_stack_var_1
        ../../gcc/cfgexpand.c:1221
0x670685 expand_one_ssa_partition
        ../../gcc/cfgexpand.c:1295
0x670685 expand_used_vars
        ../../gcc/cfgexpand.c:1940
0x671e20 execute
        ../../gcc/cfgexpand.c:6084
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64003

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |ASSIGNED
           Assignee|enkovich.gnu at gmail dot com      |ubizjak at gmail dot com

--- Comment #31 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 36051
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36051&action=edit
Patch that introduces ADJUST_INSN_LENGTH

Patch that introduces ADJUST_INSN_LENGTH and tags relevant insns with
maybe_prefix_bnd attribute.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf991

--- Comment #2 from Basile Starynkevitch <basile at starynkevitch dot net> ---
It looks like this bug is corrected in GCC 5.2 (I'm compiling the FSF tree).

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[sje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Steve Ellcey <sje at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sje at gcc dot gnu.org

--- Comment #46 from Steve Ellcey <sje at gcc dot gnu.org> ---
I see the same failures on MIPS too.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ro at gcc dot gnu.org

--- Comment #47 from Rainer Orth <ro at gcc dot gnu.org> ---
(In reply to Andreas Schwab from comment #44)

Same on sparc.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #48 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
The errors reported in comments 44, 45, 46, and 47 are fixed in the git branch
aoliva/pr64164.  I'm giving it all some more testing before posting an updated,
consolidated patch.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[gary at intrepid dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #49 from Gary Funck <gary at intrepid dot com> ---
(In reply to Alexandre Oliva from comment #48)
> The errors reported in comments 44, 45, 46, and 47 are fixed in the git
> branch aoliva/pr64164.  I'm giving it all some more testing before posting
> an updated, consolidated patch.

I applied your patch (commit 9357ff1, 8/2/15) to our GUPC branch, based off
trunk version 226386 on gcc112 (PPC64LE).  It bootstrapped fine and passed the
tests with "-O0 --enable-checking" and "-O3 --disable-checking".

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #50 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Fri Aug 14 18:51:50 2015
New Revision: 226901

URL: https://gcc.gnu.org/viewcvs?rev=226901&root=gcc&view=rev
Log:
[PR64164] Drop copyrename, use coalescible partition as base when optimizing.

for  gcc/ChangeLog

        PR rtl-optimization/64164
        PR bootstrap/66978
        PR middle-end/66983
        PR rtl-optimization/67000
        PR middle-end/67034
        PR middle-end/67035
        * Makefile.in (OBJS): Drop tree-ssa-copyrename.o.
        * tree-ssa-copyrename.c: Removed.
        * opts.c (default_options_table): Drop -ftree-copyrename.  Add
        -ftree-coalesce-vars.
        * passes.def: Drop all occurrences of pass_rename_ssa_copies.
        * common.opt (ftree-copyrename): Ignore.
        (ftree-coalesce-inlined-vars): Likewise.
        * doc/invoke.texi: Remove the ignored options above.
        * gimple-expr.h (gimple_can_coalesce_p): Move declaration
        * tree-ssa-coalesce.h: ... here.
        * tree-ssa-uncprop.c: Include tree-ssa-coalesce.h and other
        headers required by it.
        * gimple-expr.c (gimple_can_coalesce_p): Allow coalescing
        across variables when flag_tree_coalesce_vars.  Check register
        use and promoted modes to allow coalescing.  Do not coalesce
        maybe-byref parms with SSA_NAMEs of other variables, or
        anonymous SSA_NAMEs.  Moved to tree-ssa-coalesce.c.
        * tree-ssa-live.c (struct tree_int_map_hasher): Move along
        with its member functions to tree-ssa-coalesce.c.
        (var_map_base_init): Likewise.  Renamed to
        compute_samebase_partition_bases.
        (partition_view_normal): Drop want_bases parameter.
        (partition_view_bitmap): Likewise.
        * tree-ssa-live.h: Adjust declarations.
        * tree-ssa-coalesce.c: Include explow.h and cfgexpand.h.
        (build_ssa_conflict_graph): Process PARM_ and RESULT_DECLs's
        default defs at the entry point.
        (dump_part_var_map): New.
        (compute_optimized_partition_bases): New, called by...
        (coalesce_ssa_name): ... when flag_tree_coalesce_vars, instead
        of compute_samebase_partition_bases.  Adjust.
        * alias.c (nonoverlapping_memrefs_p): Disregard gimple-regs.
        * cfgexpand.c (leader_merge, parm_maybe_byref_p): New.
        (ssa_default_def_partition): New.
        (get_rtl_for_parm_ssa_default_def): New.
        (align_local_variable, add_stack_var): Support anonymous SSA
        names.
        (defer_stack_allocation): Likewise.  Declare earlier.
        (set_rtl): Merge exprs and attrs, even for MEMs and non-SSA
        vars.  Update DECL_RTL for PARM_DECLs and RESULT_DECLs too.
        Do no record deferred-allocation marker in
        SA.partition_to_pseudo.
        (expand_stack_vars): Adjust check for the marker in it.
        (expand_one_stack_var_at): Handle anonymous SSA_NAMEs.  Drop
        redundant MEM attr setting.
        (expand_one_stack_var_1): Handle anonymous SSA_NAMEs.  Renamed
        from...
        (expand_one_stack_var): ... this.  New wrapper to check and
        skip already expanded SSA partitions.
        (record_alignment_for_reg_var): New, factored out of...
        (expand_one_var): ... this.
        (expand_one_ssa_partition): New.
        (adjust_one_expanded_partition_var): New.
        (expand_one_register_var): Check and skip already expanded SSA
        partitions.
        (expand_used_vars): Don't create DECLs for anonymous SSA
        names.  Expand all SSA partitions, then adjust all SSA names.
        (pass::execute): Replace the loops that set
        SA.partition_to_pseudo from partition leaders and cleared
        DECL_RTL for multi-location variables, and that which used to
        rename vars and set attrs, with one that clears DECL_RTL and
        checks that PARMs and RESULTs default_defs match DECL_RTL.
        * cfgexpand.h (get_rtl_for_parm_ssa_default_def): Declare.
        * emit-rtl.c: Include stor-layout.h.
        (set_reg_attrs_for_parm): Handle NULL decl.
        (set_reg_attrs_for_decl_rtl): Take mode from expression if
        it's not a DECL.
        * stmt.c (emit_case_decision_tree): Pass it the SSA_NAME
        rather than its possibly-NULL DECL.
        * explow.c (promote_ssa_mode): New.
        * explow.h (promote_ssa_mode): Declare.
        * expr.c (expand_expr_real_1): Handle anonymous SSA_NAMEs.
        (read_complex_part): Export.
        * expr.h (read_complex_part): Declare.
        * cfgexpand.h (parm_maybe_byref_p): Declare.
        * function.c: Include cfgexpand.h.
        (use_register_for_decl): Handle SSA_NAMEs, anonymous or not.
        (use_register_for_parm_decl): Wrapper for the above to
        special-case the result_ptr.
        (rtl_for_parm): Ditto for get_rtl_for_parm_ssa_default_def.
        (split_complex_args): Take assign_parm_data_all argument.
        Pass it to rtl_for_parm.  Set up rtl and context for split
        args.  Reset complex parm before fetching its default decl
        rtl.
        (assign_parms_unsplit_complex): Use the default-def complex
        parm rtl if it matches the components.
        (assign_parms_augmented_arg_list): Adjust.
        (maybe_reset_rtl_for_parm): Reset DECL_RTL of parms with
        multiple locations.  Recognize split complex args.
        (assign_parm_adjust_stack_rtl): Add all and parm arguments,
        for rtl_for_parm.  For SSA-assigned parms, zero stack_parm.
        (assign_parm_setup_block): Prefer SSA-assigned location, and
        fill in its address if the memory location of a maybe-byref
        parm was not assigned by cfgexpand.
        (assign_parm_setup_reg): Likewise.  Adjust its mode as
        needed.  Use entry_parm for equiv if stack_parm is NULL.  Make
        sure passed_pointer parms don't need conversion.  Copy address
        or value as needed.
        (assign_parm_setup_stack): Prefer SSA-assigned location.
        (assign_parms): Maybe reset DECL_RTL of params.  Adjust stack
        rtl before testing for pointer bounds.  Special-case result_ptr.
        (expand_function_start): Maybe reset DECL_RTL of result.
        Prefer SSA-assigned location for result and static chain.
        Factor out DECL_RESULT and SET_DECL_RTL.  Convert static chain
        to Pmode if needed, from H.J. Lu  <hongjiu.lu@intel.com>.
        * tree-outof-ssa.c (insert_value_copy_on_edge): Handle
        anonymous SSA names.  Use promote_ssa_mode.
        (get_temp_reg): Likewise.
        (remove_ssa_form): Adjust.
        * stor-layout.c (layout_decl): Don't set mem attributes of
        non-MEMs.
        * var-tracking.c (dataflow_set_clear_at_call): Take call_insn
        and get its reg_usage for reg invalidation.
        (compute_bb_dataflow): Pass it insn.
        (emit_notes_in_bb): Likewise.

for  gcc/testsuite/ChangeLog

        * gcc.dg/guality/pr54200.c: Add -fno-tree-coalesce-vars.
        * gcc.dg/ssp-1.c: Make counter a register.
        * gcc.dg/ssp-2.c: Likewise.
        * gcc.dg/torture/parm-coalesce.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/parm-coalesce.c
Removed:
    trunk/gcc/tree-ssa-copyrename.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/Makefile.in
    trunk/gcc/alias.c
    trunk/gcc/cfgexpand.c
    trunk/gcc/cfgexpand.h
    trunk/gcc/common.opt
    trunk/gcc/doc/invoke.texi
    trunk/gcc/emit-rtl.c
    trunk/gcc/explow.c
    trunk/gcc/explow.h
    trunk/gcc/expr.c
    trunk/gcc/expr.h
    trunk/gcc/function.c
    trunk/gcc/gimple-expr.c
    trunk/gcc/gimple-expr.h
    trunk/gcc/opts.c
    trunk/gcc/passes.def
    trunk/gcc/stmt.c
    trunk/gcc/stor-layout.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/guality/pr54200.c
    trunk/gcc/testsuite/gcc.dg/ssp-1.c
    trunk/gcc/testsuite/gcc.dg/ssp-2.c
    trunk/gcc/tree-outof-ssa.c
    trunk/gcc/tree-ssa-coalesce.c
    trunk/gcc/tree-ssa-coalesce.h
    trunk/gcc/tree-ssa-live.c
    trunk/gcc/tree-ssa-live.h
    trunk/gcc/tree-ssa-uncprop.c
    trunk/gcc/var-tracking.c

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 66983, which changed state.

Bug 66983 Summary: [6 Regression] Many testsuite regressions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67034, which changed state.

Bug 67034 Summary: [6 Regression] FAIL: gcc.c-torture/compile/pr39928-1.c
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67034

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67035, which changed state.

Bug 67035 Summary: [6 Regression] FAIL: gcc.c-torture/compile/pr54713-3.c
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67035

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67000, which changed state.

Bug 67000 Summary: [6 Regression] ICE in split_complex_args, at function.c:2325 on ppc64le
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67000

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 66978, which changed state.

Bug 66978 Summary: [6 Regression] bootstrap failure with --with-multilib-list=m32,m64,mx32
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #51 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Fixed for the next major release.  Not planning a backport.

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #52 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Wed Aug 19 17:00:32 2015
New Revision: 227015

URL: https://gcc.gnu.org/viewcvs?rev=227015&root=gcc&view=rev
Log:
[PR64164] fix regressions reported on m68k and armeb

Defer stack slot address assignment for all parms that can't live in
pseudos, and accept pseudos assignments in assign_param_setup_block.

for  gcc/ChangeLog

        PR rtl-optimization/64164
        * cfgexpand.c (parm_maybe_byref_p): Renamed to...
        (parm_in_stack_slot_p): ... this.  Disregard mode, what
        matters is whether the parm will live in a pseudo or a stack
        slot.
        (expand_one_ssa_partition): Deal with params without a default
        def.  Disregard mode.
        * cfgexpand.h: Renamed function declaration.
        * tree-ssa-coalesce.c: Adjust.
        * function.c (split_complex_args): Allocate stack slot for
        unassigned parms before splitting.
        (parm_in_unassigned_mem_p): New.  Use it instead of
        parm_maybe_byref_p throughout this file.
        (assign_parm_setup_block): Use it.  Accept pseudos in the
        expand-assigned rtl.
        (assign_parm_setup_reg): Drop BLKmode requirement.
        (assign_parm_setup_stack): Allocate and fill in the address of
        unassigned MEM parms.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c
    trunk/gcc/cfgexpand.h
    trunk/gcc/function.c
    trunk/gcc/tree-ssa-coalesce.c

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #53 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Fri Aug 21 20:03:14 2015
New Revision: 227085

URL: https://gcc.gnu.org/viewcvs?rev=227085&root=gcc&view=rev
Log:
fix sched compare regression

for  gcc/ChangeLog

        PR rtl-optimization/64164
        PR rtl-optimization/67227
        * alias.c (memrefs_conflict_p): Handle VALUEs in PLUS better.
        (nonoverlapping_memrefs_p): Test offsets and sizes when given
        identical gimple_reg exprs.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/alias.c

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67227, which changed state.

Bug 67227 Summary: [6 regression] comparison failure in ada/par.o
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67227

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |67597, 67490

--- Comment #54 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
New patch posted at https://gcc.gnu.org/ml/gcc-patches/2015-09/msg01793.html


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67490
[Bug 67490] [6 regression] FAIL: gcc.target/powerpc/pr16458-1.c
scan-assembler-not cmpw
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67597
[Bug 67597] [6 Regression] profiledbootstrap failure on ppc64le

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #55 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Sun Sep 27 09:02:00 2015
New Revision: 228175

URL: https://gcc.gnu.org/viewcvs?rev=228175&root=gcc&view=rev
Log:
revert to assign_parms assignments using default defs

Revert the fragile and complicated changes to assign_parms designed to
enable it to use RTL assigments chosen by cfgexpand, and instead have
cfgexpand use the RTL assignments by assign_parms, keying them off of
the default defs that are now necessarily introduced for each parm and
result.  The possible lack of a default def was already a problem, and
the fallbacks in place were not enough, as shown by PR67312.  We now
have checking asserts in set_rtl that verify that we're assigning to
each var a piece of RTL that matches the expectations set forth by
use_register_for_decl.

for  gcc/ChangeLog

        PR rtl-optimization/64164
        PR tree-optimization/67312
        PR middle-end/67340
        PR middle-end/67490
        PR bootstrap/67597
        * cfgexpand.c (parm_in_stack_slot_p): Remove.
        (ssa_default_def_partition): Remove.
        (get_rtl_for_parm_ssa_default_def): Remove.
        (set_rtl): Check that RTL assignments match expectations.
        Loop on SUBREGs, CONCATs and PARALLELs subexprs.  Set only the
        default def location for params and results.  Record SSA names
        or types in REG and MEM attrs, respectively.
        (set_parm_rtl): New.
        (expand_one_ssa_partition): Drop logic that assigned MEMs with
        unassigned addresses.
        (adjust_one_expanded_partition_var): Don't accept NULL RTL on
        deferred stack alloc vars.
        (expand_used_vars): Skip partitions holding parm default defs.
        Move adjust_one_expanded_partition_var loop...
        (pass_expand::execute): ... here.  Drop redundant assert.
        Adjust comments before the final loop over all ssa names.
        Require assigned rtl of parms and results to match exactly.
        Reset its attributes to match them, not any other variables in
        the same partition.
        (expand_debug_expr): Use entry value for PARM's default defs
        only iff they have zero nondebug uses.
        * cfgexpand.h (parm_in_stack_slot_p): Remove.
        (get_rtl_for_parm_ssa_default_def): Remove.
        (set_parm_rtl): Declare.
        * doc/invoke.texi: Improve wording.
        * explow.c (promote_decl_mode): Fix promote_function_mode for
        result decls not by reference.
        (promote_ssa_mode): Disregard BLKmode from promote_decl, and
        bypass TYPE_MODE to get the actual vector mode.
        * function.c: Include tree-dfa.h.  Revert 2015-08-14's and
        2015-08-19's changes as follows.  Drop include of
        basic-block.h and df.h.
        (rtl_for_parm): Remove.
        (maybe_reset_rtl_for_parm): Remove.
        (parm_in_unassigned_mem_p): Remove.
        (use_register_for_decl): Add logic for RESULT_DECLs matching
        assign_parms' behavior.
        (split_complex_args): Revert.
        (assign_parms_augmented_arg_list): Revert.  Add comment
        referencing the logic above.
        (assign_parm_adjust_stack_rtl): Revert.
        (assign_parm_setup_block): Revert.  Use set_parm_rtl instead
        of SET_DECL_RTL.  Set up a REG if the parm demands so.
        (assign_parm_setup_reg): Revert.  Consolidated SET_DECL_RTL
        calls into a single set_parm_rtl.  Set up a temporary RTL
        temporarily for expand_assignment.
        (assign_parm_setup_stack): Revert.  Use set_parm_rtl.
        (assign_parms_unsplit_complex): Revert.  Use set_parm_rtl.
        (assign_bounds): Revert.
        (assign_parms): Revert.  Use set_parm_rtl.
        (allocate_struct_function): Relayout result and parms of
        non-abstruct functions.
        (expand_function_start): Revert.  Use set_parm_rtl.  If the
        result is not a hard reg, create a pseudo from the promoted
        mode of the default def.  Promote static chain mode.
        * tree-outof-ssa.c (remove_ssa_form): Drop unused
        partition_has_default_def.  Set up
        partitions_for_parm_default_defs.
        (finish_out_of_ssa): Remove partition_has_default_def.
        Release partitions_for_parm_default_defs.
        * tree-outof-ssa.h (struct ssaexpand): Remove
        partition_has_default_def.  Add
        partitions_for_parm_default_defs.
        * tree-ssa-coalesce.c: Include tree-dfa.h, tm_p.h and
        stor-layout.h.
        (build_ssa_conflict_graph): Fix conflict-detection of default
        defs of even unused default defs of params and results.
        (for_all_parms): New.
        (create_default_def): New.
        (register_default_def): New.
        (coalesce_with_default): New.
        (create_outofssa_var_map): Create default defs for all parms
        and results, and register their partitions.  Add GIMPLE_RETURN
        operands as coalesce candidates with results.  Add default
        defs of each parm or result as coalesce candidates with its
        other defs.  Mark each result def, and each default def of
        parms, as used_in_copy.
        (gimple_can_coalesce_p): Call it.  Call use_register_for_decl
        with the ssa names, even anonymous ones.  Drop
        parm_in_stack_slot_p calls.  Require same signedness and
        alignment.
        (coalesce_ssa_name): Add coalesce candidates for all defs of
        each parm and result, even unused ones.
        (parm_default_def_partition_arg): New type.
        (set_parm_default_def_partition): New.
        (get_parm_default_def_partitions): New.
        * tree-ssa-coalesce.h (get_parm_default_def_partitions): New.
        * tree-ssa-live.c (partition_view_init): Regard unused defs of
        parms and results as used.
        (verify_live_on_entry): Don't error out just because they're
        not live.

for  gcc/testsuite/ChangeLog

        PR rtl-optimization/64164
        PR tree-optimization/67312
        * gcc.dg/pr67312.c: New.  From Zdenek Sojka.
        * gcc.target/i386/stackalign/return-4.c: Add -O.

Added:
    trunk/gcc/testsuite/gcc.dg/pr67312.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c
    trunk/gcc/cfgexpand.h
    trunk/gcc/doc/invoke.texi
    trunk/gcc/explow.c
    trunk/gcc/function.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.target/i386/stackalign/return-4.c
    trunk/gcc/tree-outof-ssa.c
    trunk/gcc/tree-outof-ssa.h
    trunk/gcc/tree-ssa-coalesce.c
    trunk/gcc/tree-ssa-coalesce.h
    trunk/gcc/tree-ssa-live.c

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67597, which changed state.

Bug 67597 Summary: [6 Regression] profiledbootstrap failure on ppc64le
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67597

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67490, which changed state.

Bug 67490 Summary: [6 regression] FAIL: gcc.target/powerpc/pr16458-1.c scan-assembler-not cmpw
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67490

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67312, which changed state.

Bug 67312 Summary: [6 Regression] ICE: SIGSEGV in expand_expr_real_1 (expr.c:9561) with -ftree-coalesce-vars
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67312

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67340, which changed state.

Bug 67340 Summary: [6 Regression] ICE:  in convert_move, at expr.c:279
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67340

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67766, which changed state.

Bug 67766 Summary: [6 Regression]: Bootstrap failure on alpha-linux-gnu: ICE in simplify_subreg, at simplify-rtx.c
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67766

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164
Bug 64164 depends on bug 67891, which changed state.

Bug 67891 Summary: [6 Regression] FAIL: gcc.dg/pr43300.c (internal compiler error) on alpha-linux-gnu
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67891

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED