[Bug c/21173] New: miscompiled pointer subtraction broke Linux kernel

[Bug c/21173] New: miscompiled pointer subtraction broke Linux kernel

[mikpe at csd dot uu dot se]

/* gcc4pointersubtractionbug.c
 * Written by Mikael Pettersson, mikpe@csd.uu.se, 2005-04-23.
 *
 * This program illustrates a code optimisation bug in
 * gcc-4.0.0 (final) and gcc-4.0.0-20050417, where a pointer
 * subtraction operation is compiled as a pointer addition.
 * Observed at -O2. gcc was configured for i686-pc-linux-gnu.
 *
 * This bug broke net/ipv4/devinet.c:devinet_sysctl_register()
 * in the linux-2.6.12-rc2 Linux kernel, causing /sbin/sysctl
 * to trigger kernel oopses.
 *
 * gcc-4.0.0-20050416 and earlier prereleases do not have this bug.
 */
#include <stdio.h>
#include <string.h>

#define NRVARS  5

struct ipv4_devconf {
    int var[NRVARS];
};
struct ipv4_devconf ipv4_devconf[2];

struct ctl_table {
    void *data;
};

struct devinet_sysctl_table {
    struct ctl_table devinet_vars[NRVARS];
};

void devinet_sysctl_relocate(struct devinet_sysctl_table *t,
                             struct ipv4_devconf *p)
{
    int i;

    for (i = 0; i < NRVARS; i++)
        /* Initially data points to a field in ipv4_devconf[0].
           This code relocates it to the corresponding field in *p.
           At -O2, gcc-4.0.0-20050417 and gcc-4.0.0 (final)
           miscompile this pointer subtraction as a pointer addition. */
        t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf[0];
}

struct devinet_sysctl_table devinet_sysctl;

int main(void)
{
    struct devinet_sysctl_table t;
    int i;

    for(i = 0; i < NRVARS; i++)
        devinet_sysctl.devinet_vars[i].data = &ipv4_devconf[0].var[i];

    memcpy(&t, &devinet_sysctl, sizeof t);
    devinet_sysctl_relocate(&t, &ipv4_devconf[1]);

    for(i = 0; i < NRVARS; i++)
        if (t.devinet_vars[i].data != &ipv4_devconf[1].var[i]) {
            fprintf(stderr, "t.devinet_vars[%u].data == %p, should be %p\n",
                    i,
                    t.devinet_vars[i].data,
                    &ipv4_devconf[1].var[i]);
            return 1;
        }

    printf("all ok\n");
    return 0;
}

-- 
           Summary: miscompiled pointer subtraction broke Linux kernel
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mikpe at csd dot uu dot se
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug c/21173] miscompiled pointer subtraction broke Linux kernel

[belyshev at depni dot sinp dot msu dot ru]

------- Additional Comments From belyshev at depni dot sinp dot msu dot ru  2005-04-23 11:56 -------
*** Bug 21175 has been marked as a duplicate of this bug. ***

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug c/21173] miscompiled pointer subtraction broke Linux kernel

[azarah at gentoo dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |azarah at gentoo dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0 regression] miscompiled pointer subtraction broke Linux kernel

[belyshev at depni dot sinp dot msu dot ru]

------- Additional Comments From belyshev at depni dot sinp dot msu dot ru  2005-04-23 12:30 -------
// Confirmed on amd64 too, smaller testcase (compile with -O2):

void abort (void);

char q;
void *a[2];

void foo (char *p)
{
  int i;
  for (i = 0; i < 2; i++)
    a[i] += p - &q;
}

int main (void)
{
  int i;
  foo (&q);
  for (i = 0; i < 2; i ++)
    if (a[i])
      abort ();
  return 0;
}


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|c                           |tree-optimization
     Ever Confirmed|                            |1
  GCC build triplet|i686-pc-linux-gnu           |
   GCC host triplet|i686-pc-linux-gnu           |
 GCC target triplet|i686-pc-linux-gnu           |
           Keywords|                            |wrong-code
      Known to fail|                            |4.0.0
      Known to work|                            |3.4.4
           Priority|P2                          |P1
   Last reconfirmed|0000-00-00 00:00:00         |2005-04-23 12:30:26
               date|                            |
            Summary|miscompiled pointer         |[4.0 regression] miscompiled
                   |subtraction broke Linux     |pointer subtraction broke
                   |kernel                      |Linux kernel
   Target Milestone|---                         |4.0.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[belyshev at depni dot sinp dot msu dot ru]

------- Additional Comments From belyshev at depni dot sinp dot msu dot ru  2005-04-23 12:51 -------
-O1 -ftree-pre causing this.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org
      Known to fail|4.0.0                       |4.0.0 4.1.0
            Summary|[4.0 regression] miscompiled|[4.0/4.1 regression]
                   |pointer subtraction broke   |miscompiled pointer
                   |Linux kernel                |subtraction broke Linux
                   |                            |kernel


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-23 13:18 -------
Hmm, is -&a legal gimple, if it is then it is a PRE bug, otherwise it is a bug in the gimplifier.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-04-23 13:24 -------
.crited dump: 
 
foo (p) 
{ 
  int i; 
  void * D.1576; 
  char * D.1575; 
  void * D.1574; 
  void * D.1573; 
  int i.0; 
 
<bb 0>: 
 
  # i_16 = PHI <i_13(3), 0(0)>; 
<L0>:; 
  D.1573_7 = a[i_16]; 
  D.1574_9 = D.1573_7 + p_8; 
  D.1575_10 = -&q; 
  D.1576_11 = D.1574_9 + D.1575_10; 
  a[i_16] = D.1576_11; 
  i_13 = i_16 + 1; 
  if (i_13 <= 1) goto <L6>; else goto <L2>; 
 
<L6>:; 
  goto <bb 1> (<L0>); 
 
<L2>:; 
  return; 
 
} 
 
.pre dump: 
foo (p) 
{ 
  int pretmp.3; 
  char * pretmp.2; 
  int i; 
  void * D.1576; 
  char * D.1575; 
  void * D.1574; 
  void * D.1573; 
  int i.0; 
 
<bb 0>: 
  pretmp.2_6 = &q; 
 
  # i_16 = PHI <i_13(3), 0(0)>; 
<L0>:; 
  D.1573_7 = a[i_16]; 
  D.1574_9 = D.1573_7 + p_8; 
  D.1575_10 = pretmp.2_6; 
  D.1576_11 = D.1574_9 + D.1575_10; 
  a[i_16] = D.1576_11; 
  i_13 = i_16 + 1; 
  if (i_13 <= 1) goto <L6>; else goto <L2>; 
 
<L6>:; 
  goto <bb 1> (<L0>); 
 
<L2>:; 
  return; 
 
} 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-04-23 13:36 -------
This could be the same bug as the one reported on the mailing list here: 
http://gcc.gnu.org/ml/gcc/2005-04/msg01260.html 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-04-23 13:39 -------
ob-vi-ous... 
 
Index: tree-ssa-pre.c 
=================================================================== 
RCS file: /cvs/gcc/gcc/gcc/tree-ssa-pre.c,v 
retrieving revision 2.80 
diff -u -3 -p -r2.80 tree-ssa-pre.c 
--- tree-ssa-pre.c      21 Apr 2005 18:05:27 -0000      2.80 
+++ tree-ssa-pre.c      23 Apr 2005 13:38:52 -0000 
@@ -1391,7 +1391,7 @@ create_expression_by_pieces (basic_block 
        if (!is_gimple_min_invariant (genop1)) 
          newexpr = force_gimple_operand (folded, &forced_stmts, false, NULL); 
        else 
-         newexpr = genop1; 
+         newexpr = folded; 
        if (forced_stmts) 
          { 
            tsi = tsi_start (forced_stmts); 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[jakub at gcc dot gnu dot org]

------- Additional Comments From jakub at gcc dot gnu dot org  2005-04-23 14:59 -------
Shouldn't that be then also:
-  if (!is_gimple_min_invariant (genop1))
+  if (!is_gimple_min_invariant (folded))
?


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[dberlin at dberlin dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-23 15:09 -------
Subject: Re:  [4.0/4.1 regression] miscompiled
	pointer subtraction broke Linux kernel

On Sat, 2005-04-23 at 14:59 +0000, jakub at gcc dot gnu dot org wrote:
> ------- Additional Comments From jakub at gcc dot gnu dot org  2005-04-23 14:59 -------
> Shouldn't that be then also:
> -  if (!is_gimple_min_invariant (genop1))
> +  if (!is_gimple_min_invariant (folded))
> ?
> 
> 

yes

In fact, the error actually makes no sense (IE you guys are overlooking
an important fact).

is_gimple_min_invariants are legal operands to unary expressions,
regardless of whether they are "complex" or not, or so i was told.

So if genop1 is is_gimple_min_invariant, it should be fine there, and
you shouldn't need to use folded.

If it wasn't, we'd force_gimple_operand it.

I'm pretty sure you are just covering up a disconnect in what we allow
as gimple and what we handle.




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[dberlin at dberlin dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-23 15:13 -------
Subject: Re:  [4.0/4.1 regression] miscompiled
	pointer subtraction broke Linux kernel

> yes
> 
> In fact, the error actually makes no sense (IE you guys are overlooking
> an important fact).
> 
> is_gimple_min_invariants are legal operands to unary expressions,
> regardless of whether they are "complex" or not, or so i was told.
> 
> So if genop1 is is_gimple_min_invariant, it should be fine there, and
> you shouldn't need to use folded.
> 

Forget it, genop1 doens't include the operation, and folded does. 
I forgot about that




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[azarah at gentoo dot org]

------- Additional Comments From azarah at gentoo dot org  2005-04-23 17:19 -------
Patch from comment #7 seems to work here (doing make check now to verify).  I
assume the change Jakub asked about is not needed?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-04-23 19:37 -------
Created an attachment (id=8718)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8718&action=view)
patch

Jakub, your patch is wrong.  Try this one.


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[stevenb at suse dot de]

------- Additional Comments From stevenb at suse dot de  2005-04-23 23:01 -------
Subject: Re:  [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

Yeah, well, ehm...

The original bug resurfaces with my patch.  This happens because
is_gimple_reg_rhs only looks at the outermost level of the expression,
e.g. it happily accepts "(intD.0) -xD.1566_4" as a valid GIMPLE rhs.

Obviously this is wrong.

I'm testing a new patch that simply always runs force_gimple_operand
on folded, it's not clear to me why we don't do that anyway (it is
cheap and safer).



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[stevenb at suse dot de]

------- Additional Comments From stevenb at suse dot de  2005-04-24 09:23 -------
Subject: Re:  [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

On Sunday 24 April 2005 05:36, dberlin at dberlin dot org wrote:
> Uh, because it causes things to become non-invariant when they were
> originally invariant (because it will *always* create a new name for
> them).

Well, the comment before force_gimple_operand says it should not:

/* Expands EXPR to list of gimple statements STMTS.  If SIMPLE is true,
   force the result to be either ssa_name or an invariant, otherwise
   just force it to be a rhs expression.  If VAR is not NULL, make the
   base variable of the final destination be VAR if suitable.  */

tree
force_gimple_operand (tree expr, tree *stmts, bool simple, tree var)
{


tree-ssa-pre uses force_gimple_operand with SIMPLE==false, so if
expr is already a valid rhs, force_gimple_operand should do nothing.
If it does, I consider that to be a bug.

Your patch to use unshare_expr is IMHO unnecessarily expensive.



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[dberlin at gcc dot gnu dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-24 15:19 -------
Please compile the testcase from 20963, with and without the unshare_expr in the
patch i posted, and you'll see the bug.  force_gimple_operand replaces
TREE_OPERAND (folded, 0) with something else. folded came directly from the
ANTIC set, so we can't touch it like that (we'd have to make it copy first).

force_gimple_operand is replacing operands in what we pass it, which causes
errors for us.
You *need* to either fix it, or pass it a copy of the expression.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[dberlin at dberlin dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-24 15:27 -------
Subject: Re:  [4.0/4.1 regression] miscompiled
	pointer subtraction broke Linux kernel


> tree-ssa-pre uses force_gimple_operand with SIMPLE==false, so if
> expr is already a valid rhs, force_gimple_operand should do nothing.
> If it does, I consider that to be a bug.
> 
> Your patch to use unshare_expr is IMHO unnecessarily expensive.
> 
> 
> 

Here's the gdb trace, btw:

 Breakpoint 3, create_expression_by_pieces (block=0x400c4870,
expr=0x88403f0, stmts=0x400c6510) at tree-ssa-pre.c:1322

expr came from a node in ANTIC_IN, we *can't* modify it, because it's
not a copy.


(gdb) p debug_generic_stmt (expr)
(charD.3 *) &0B->typeD.1681;
...

1388            newexpr = force_gimple_operand (folded,
(gdb) n
1390            if (forced_stmts)
(gdb) p debug_generic_stmt (expr)
(charD.3 *) &D.1708_3->typeD.1681;

tada!


This is the reason we have to unshare it before passing it in.




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-25 13:59 -------
Subject: Bug 21173

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dberlin@gcc.gnu.org	2005-04-25 13:59:39

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

Log message:
	2005-04-25  Steven Bosscher  <stevenb@suse.de>
	
	Fix PR tree-optimization/21173
	
	* tree-ssa-pre.c (create_expression_by_pieces): Simplify code.
	Unshare expression we pass to force_gimple_operand.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8450&r2=2.8451
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-pre.c.diff?cvsroot=gcc&r1=2.81&r2=2.82



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-25 14:03 -------
Subject: Bug 21173

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-4_0-branch
Changes by:	dberlin@gcc.gnu.org	2005-04-25 14:02:38

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

Log message:
	2005-04-25  Daniel Berlin  <dberlin@dberlin.org>
	
	Fix PR tree-optimization/21173
	
	* tree-ssa-pre.c (create_expression_by_pieces): Call unshare_expr
	on things we pass to force_gimple_operand.  Don't try to special
	case min_invariants.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.7592.2.192&r2=2.7592.2.193
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-pre.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.65.4.2&r2=2.65.4.3



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-25 14:18 -------
Subject: Bug 21173

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dberlin@gcc.gnu.org	2005-04-25 14:18:31

Added files:
	gcc/testsuite/gcc.c-torture/execute: pr21173.c 

Log message:
	Testcase for pr 21173

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/execute/pr21173.c.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-25 14:47 -------
*** Bug 21167 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |joc at presence-pc dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[jakub at gcc dot gnu dot org]

------- Additional Comments From jakub at gcc dot gnu dot org  2005-04-25 14:49 -------
Are you going to commit the testcase to the branch as well?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[dberlin at dberlin dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-25 15:18 -------
Subject: Re:  [4.0/4.1 regression] miscompiled
	pointer subtraction broke Linux kernel

On Mon, 2005-04-25 at 14:49 +0000, jakub at gcc dot gnu dot org wrote:
> ------- Additional Comments From jakub at gcc dot gnu dot org  2005-04-25 14:49 -------
> Are you going to commit the testcase to the branch as well?
> 
> 
Yes

i'm waiting for a lock




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[dberlin at gcc dot gnu dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-26 12:35 -------
Fixed

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[belyshev at depni dot sinp dot msu dot ru]

------- Additional Comments From belyshev at depni dot sinp dot msu dot ru  2005-04-28 02:34 -------
*** Bug 21248 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pete at flooble dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-28 23:38 -------
Subject: Bug 21173

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	apple-local-200502-branch
Changes by:	dalej@gcc.gnu.org	2005-04-28 23:38:11

Modified files:
	gcc            : ChangeLog.apple-ppc tree-ssa-pre.c 

Log message:
	2005-04-28  Dale Johannesen  <dalej@apple.com>
	
	Radar 4100712 (PR 21173, Dan Berlin's patch)
	
	* tree-ssa-pre.c (create_expression_by_pieces): Call unshare_expr
	on things we pass to force_gimple_operand.  Don't try to special
	case min_invariants.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.apple-ppc.diff?cvsroot=gcc&only_with_tag=apple-local-200502-branch&r1=1.1.4.53&r2=1.1.4.54
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-pre.c.diff?cvsroot=gcc&only_with_tag=apple-local-200502-branch&r1=2.64.2.2&r2=2.64.2.3



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-10 17:32 -------
*** Bug 21482 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Tobias dot Kranz at bka dot
                   |                            |bund dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-10 22:31 -------
*** Bug 21505 has been marked as a duplicate of this bug. ***

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                 CC|                            |pbriggs at clinitech dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-11 10:51 -------
*** Bug 21511 has been marked as a duplicate of this bug. ***

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                 CC|                            |nkukard at lbsd dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-17 11:34 -------
*** Bug 21618 has been marked as a duplicate of this bug. ***

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           What    |Removed                     |Added
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                 CC|                            |andreas at florath dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-18 06:04 -------
*** Bug 21640 has been marked as a duplicate of this bug. ***

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           What    |Removed                     |Added
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                 CC|                            |arjones at simultan dot
                   |                            |dyndns dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-22 18:47 -------
*** Bug 21711 has been marked as a duplicate of this bug. ***

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           What    |Removed                     |Added
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                 CC|                            |terry-palmer at btconnect
                   |                            |dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-06-12 13:24 -------
*** Bug 22032 has been marked as a duplicate of this bug. ***

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           What    |Removed                     |Added
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                 CC|                            |pb at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Comment #40 from pinskia at gcc dot gnu dot org  2006-03-28 17:40 -------
*** Bug 26903 has been marked as a duplicate of this bug. ***


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173

[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[pinskia at gcc dot gnu dot org]

------- Comment #39 from pinskia at gcc dot gnu dot org  2006-03-22 20:54 -------
*** Bug 26811 has been marked as a duplicate of this bug. ***


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
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                 CC|                            |cprincipato at dialamerica
                   |                            |dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173