[Bug optimization/14498] New: ICE on legal (varargs)

[Bug optimization/14498] New: ICE on legal (varargs)

[dalej at gcc dot gnu dot org]

Compile with -O2 and watch the ICE:

#include <stdarg.h>
extern void baz(char *);
void bar (va_list *args)
{
  if (args)
    {
      char *s = va_arg(*args, char *);
      baz(s);
    }
}

Gimplifier marks args as volatile when it sees the va_arg but does not propagate this backwards to 
regenerate gimpl for the test of args.

-- 
           Summary: ICE on legal (varargs)
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dalej at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: powerpc-apple-darwin7.2.0
  GCC host triplet: powerpc-apple-darwin7.2.0
GCC target triplet: powerpc-apple-darwin7.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-09 01:55 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-03-09 01:55:42
               date|                            |
            Summary|ICE on legal (varargs)      |[tree-ssa] ICE on legal
                   |                            |(varargs)
   Target Milestone|---                         |tree-ssa


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dalej at gcc dot gnu dot org]

------- Additional Comments From dalej at gcc dot gnu dot org  2004-03-09 02:15 -------
It seems to work to move VA_ARG handling back into the unsharing pass, but that's ugly.



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-09 03:10 -------
The right fix is really to lower varargs like the FIXME's say to do.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-10 18:57 -------
This effects perl in SPEC 2000.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
           Severity|normal                      |critical
      Known to fail|                            |tree-ssa
      Known to work|                            |3.4.0
   Last reconfirmed|2004-03-09 01:55:42         |2004-03-10 18:57:52
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-10 23:13 -------
It also effects perl in SPEC 2004 and most likely perl every where.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2004-03-10 18:57:52         |2004-03-10 23:13:57
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-13 06:31 -------
>From bug 13737:
AFAIK it is incorrect to use "va_list *" so the code is wrong.
va_list is allowed to be something different that a pointer, for example
on ppc64 and x86-64 it is an one element array (builtin type).
Arrays are always passed as a pointer to the first element so there is no
performance penalty.

>From this other bug I do not know if this is valid code (even though it is used in SPEC 
2000 or 2004) so maybe this should rejected.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[falk dot hueffner at student dot uni-tuebingen dot de]

------- Additional Comments From falk dot hueffner at student dot uni-tuebingen dot de  2004-03-13 12:19 -------
Subject: Re:  [tree-ssa] ICE on legal (varargs)

"pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

> ------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-13 06:31 -------
> From this other bug I do not know if this is valid code (even though
> it is used in SPEC 2000 or 2004) so maybe this should rejected.

I'm pretty sure it's valid. At least I don't see anything specific in
the standard which it might violate.



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dalej at apple dot com]

------- Additional Comments From dalej at apple dot com  2004-03-14 18:53 -------
C99 has a footnote 212 which says explicitly that pointers to va_list are allowed.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dalej at gcc dot gnu dot org]

------- Additional Comments From dalej at gcc dot gnu dot org  2004-03-15 19:58 -------
I've attached a patch on the lines in comment #2.  I don't claim this is the best way to fix it,
but this seems to work.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dnovillo at gcc dot gnu dot org]

------- Additional Comments From dnovillo at gcc dot gnu dot org  2004-03-15 21:34 -------

The patch will extend the hack to cover more cases, but it's not clear that it 
will be enough to cover all cases.

If we are going to keep ducking the issue, we might as well hack VA_ARG_EXPRs 
early enough to avoid gimplification problems.  The attached patch marks 
volatile the operand of a VA_ARG_EXPR right after we build it.

Richard, I've assigned the PR to you.  If the real fix is too intrusive to be 
done before the merge, then I'd suggest we use this hack until a real fix is 
done post merge.  The hack fixes the PR but it still needs testing.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rth at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dnovillo at gcc dot gnu dot org]

------- Additional Comments From dnovillo at gcc dot gnu dot org  2004-03-15 22:25 -------

I was wrong, Dale's patch from comment #9 should be enough.  I forgot that by
marking the operands volatile too early we cause spurious FE warnings.

Dale, if your patch survives bootstrap and testing it's OK to go in.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dalej at apple dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dalej at gcc dot gnu dot org]

------- Additional Comments From dalej at gcc dot gnu dot org  2004-03-15 22:43 -------
OK, I'll run a test cycle.  Leaving assigned to rth in the meantime since he hasn't commented yet;
if satisfied with this solution, he can assign it to me.
 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dnovillo at redhat dot com]

------- Additional Comments From dnovillo at redhat dot com  2004-03-15 22:49 -------
Subject: Re:  [tree-ssa] ICE on legal (varargs)

On Mon, 2004-03-15 at 17:43, dalej at gcc dot gnu dot org wrote:
> ------- Additional Comments From dalej at gcc dot gnu dot org  2004-03-15 22:43 -------
> OK, I'll run a test cycle.  Leaving assigned to rth in the meantime since he hasn't commented yet;
> if satisfied with this solution, he can assign it to me.
>  
He has, on IRC:

<dnovillo> rth: re VA_ARG_EXPR.  we might as well hack it good, then.  eventually fix it after the merge.
<rth> dnovillo: yeah.
<rth> dnovillo: when i was looking at this last time, i stalled on amd64.
<rth> dnovillo: it's really really ugly.


Diego.



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dnovillo at gcc dot gnu dot org]

------- Additional Comments From dnovillo at gcc dot gnu dot org  2004-03-16 16:04 -------
Dale,

FYI.  Your patch survived bootstrap and regtesting on x86 and x86-64.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-03-16 19:06 -------
Subject: Bug 14498

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	tree-ssa-20020619-branch
Changes by:	dalej@gcc.gnu.org	2004-03-16 19:05:57

Modified files:
	gcc            : gimplify.c ChangeLog.tree-ssa 

Log message:
	2004-03-16  Dale Johannesen  <dale@apple.com>
	
	PR optimization/14498
	* gimplify.c (copy_if_shared_r): Mark VA_ARGS_EXPRs as volatile.
	(mark_decls_volatile_r): Moved higher in file (unchanged).

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/gimplify.c.diff?cvsroot=gcc&only_with_tag=tree-ssa-20020619-branch&r1=1.1.2.144&r2=1.1.2.145
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.tree-ssa.diff?cvsroot=gcc&only_with_tag=tree-ssa-20020619-branch&r1=1.1.2.1273&r2=1.1.2.1274



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug optimization/14498] [tree-ssa] ICE on legal (varargs)

[dalej at gcc dot gnu dot org]

------- Additional Comments From dalej at gcc dot gnu dot org  2004-03-16 19:08 -------
Passed on darwin also, checked in.


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498

[Bug rtl-optimization/14498] [tree-ssa] ICE on legal (varargs)

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-05-28 17:09 -------
Subject: Bug 14498

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dalej@gcc.gnu.org	2004-05-28 17:09:22

Added files:
	gcc/testsuite/gcc.dg: va-arg-3.c 

Log message:
	New, from PR 14498.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/va-arg-3.c.diff?cvsroot=gcc&r1=NONE&r2=1.1



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14498