[Bug c++/25979] New: incorrect codegen for conditional

[Bug c++/25979] New: incorrect codegen for conditional

[hhinnant at apple dot com]

I'm not positive whether or not this is a duplicate of 25895.  I figured I'd
better enter it just in case it wasn't.  Test case:

#include <stdio.h>

struct A
{
    A() : data1_(0), data2_(0) {}
    A(int i, int j) : data1_(i), data2_(j) {}
    A operator+(int);
    friend A operator+(int, const A&);
    ~A() {}
//private:
    int data1_;
    int data2_;
};

extern bool x;

void display(const A& x)
{
    printf("%d %d\n", x.data1_, x.data2_);
}

int main()
{
    A a1(1,2);
    a1 = (x ? a1 + 3 : 3 + a1);
    display(a1);
}

bool x = false;

A
A::operator+(int i)
{
    A a;
    a = *this;
    a.data2_ = i;
    return a;
}

A
operator+(int i, const A& x)
{
    A a;
    a = x;
    a.data1_ = i;
    return a;
}

Output:

3 0

Expected output:

3 2

The gimple tree (-fdump-tree-gimple) is showing statements like:

              operator+ (&a1, 3, &a1) [return slot addr];

which shoud instead be:

             operator+ (temp, 3, &a1) [return slot addr];
             ...
             a1 = temp;

The bad codegen is sensitive to the presence or absence of special member
functions.  For example if you comment out ~A(), you get the expected output.


-- 
           Summary: incorrect codegen for conditional
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hhinnant at apple dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] incorrect codegen for conditional

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-01-26 17:31 -------
This is actually a dup of bug 25977.  But I think it was worked around in 4.0.2
(or maybe just 4.0.3, I have to double check that).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] incorrect codegen for conditional

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2006-01-26 17:36 -------
It was worked around in 4.0.2 (done on 2005-04-05 23:13:35) by:

        PR c++/19317
        * calls.c (expand_call): Disable return slot optimization.

Which just disabled the return slot optimization for 4.0.x

Now 4.1.0 never got that patch but a different one which fixed a similar bug
(PR 19317) but it did not fix this one or the duplicated one.

*** This bug has been marked as a duplicate of 25977 ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] incorrect codegen for conditional

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-01-26 17:39 -------
Actually this is not a full dup as this one is also still broken on the 4.0
branch.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|DUPLICATE                   |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2006-01-26 17:43 -------
Confirmed, very much related to PR 25977.  Though I think this and PR 25977 are
almost the same bug as we get:
TARGET_EXPR <D.3014, <<< Unknown tree: aggr_init_expr
  operator+
  3, (struct A &) (struct A *) &a1
  D.3014 >>>

We are losing some piece of information.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |25977
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |wrong-code
      Known to fail|                            |4.0.3 4.1.0 4.2.0
      Known to work|                            |3.4.0
   Last reconfirmed|0000-00-00 00:00:00         |2006-01-26 17:43:24
               date|                            |
            Summary|incorrect codegen for       |[4.0/4.1/4.2 Regression]
                   |conditional                 |incorrect codegen for
                   |                            |conditional [SVO issue]
   Target Milestone|---                         |4.0.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jason at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-01-26 17:43:24         |2006-01-27 20:09:50
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[mmitchel at gcc dot gnu dot org]

------- Comment #5 from mmitchel at gcc dot gnu dot org  2006-02-01 03:07 -------
Jason, do you have an ETA on this bug?


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

------- Comment #6 from jason at gcc dot gnu dot org  2006-02-03 21:56 -------
Subject: Bug 25979

Author: jason
Date: Fri Feb  3 21:56:03 2006
New Revision: 110564

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110564
Log:
        PR c++/25979
        * gimplify.c (gimplify_modify_expr_rhs): Disable *& optimization for
now.

        PR middle-end/25977
        * gimplify.c (gimplify_modify_expr_rhs): It's not always safe to do RVO
        on the return slot if it's an NRV.

Added:
    branches/gcc-4_1-branch/gcc/testsuite/g++.dg/opt/nrv10.C
    branches/gcc-4_1-branch/gcc/testsuite/g++.dg/opt/nrv11.C
Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/gimplify.c
    branches/gcc-4_1-branch/gcc/testsuite/g++.dg/opt/temp1.C


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

------- Comment #7 from jason at gcc dot gnu dot org  2006-02-03 21:57 -------
Subject: Bug 25979

Author: jason
Date: Fri Feb  3 21:57:08 2006
New Revision: 110565

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110565
Log:
        PR c++/25979
        * gimplify.c (gimplify_modify_expr_rhs): Disable *& optimization for
now.

        PR middle-end/25977
        * gimplify.c (gimplify_modify_expr_rhs): It's not always safe to do RVO
        on the return slot if it's an NRV.

Added:
    trunk/gcc/testsuite/g++.dg/opt/nrv10.C
    trunk/gcc/testsuite/g++.dg/opt/nrv11.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimplify.c
    trunk/gcc/testsuite/g++.dg/opt/temp1.C


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0/4.1/4.2 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

------- Comment #8 from jason at gcc dot gnu dot org  2006-02-03 21:59 -------
Fixed in 4.1 and 4.2 by disabling the fix for c++/16405 (a missed optimization
regression).  Working on a better fix.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0 Regression] incorrect codegen for conditional [SVO issue]

[steven at gcc dot gnu dot org]

------- Comment #9 from steven at gcc dot gnu dot org  2006-02-04 10:34 -------
No longer a 4.1/4.2 regression.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.0/4.1/4.2 Regression]    |[4.0 Regression] incorrect
                   |incorrect codegen for       |codegen for conditional [SVO
                   |conditional [SVO issue]     |issue]


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

------- Comment #10 from jason at gcc dot gnu dot org  2006-02-09 09:54 -------
Subject: Bug 25979

Author: jason
Date: Thu Feb  9 09:54:36 2006
New Revision: 110789

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110789
Log:
        PR c++/25979
        * tree.def: Elaborate on difference from MODIFY_EXPR.
        * doc/c-tree.texi (INIT_EXPR): Likewise.
        * gimplify.c (internal_get_tmp_var): Use INIT_EXPR.
        (gimplify_decl_expr, gimplify_init_ctor_eval): Likewise.
        (gimplify_target_expr): Likewise.
        (gimplify_cond_expr): Remove target handling.
        (gimplify_modify_expr): Don't clobber INIT_EXPR code here.
        (gimplify_expr): Clobber it here.
        (gimplify_modify_expr_rhs): Push assignment into COND_EXPR here.
        Do return slot optimization if we have an INIT_EXPR.

        PR tree-opt/24365
        * tree-inline.c (declare_return_variable): Also clear
        DECL_COMPLEX_GIMPLE_REG_P as needed in the modify_dest case.

        PR c++/16405
        * gimplify.c (gimplify_modify_expr_rhs): Re-enable *& handling.

        PR middle-end/22439
        * gimplify.c (gimplify_one_sizepos): Fix typo.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-gimplify.c
    trunk/gcc/cp/typeck2.c
    trunk/gcc/doc/c-tree.texi
    trunk/gcc/gimplify.c
    trunk/gcc/testsuite/g++.dg/opt/temp1.C
    trunk/gcc/tree-inline.c
    trunk/gcc/tree.def


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

------- Comment #11 from jason at gcc dot gnu dot org  2006-02-10 17:32 -------
Subject: Bug 25979

Author: jason
Date: Fri Feb 10 17:32:10 2006
New Revision: 110838

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110838
Log:
        PR c++/25979
        * tree.def: Elaborate on difference from MODIFY_EXPR.
        * doc/c-tree.texi (INIT_EXPR): Likewise.
        * gimplify.c (internal_get_tmp_var): Use INIT_EXPR.
        (gimplify_decl_expr, gimplify_init_ctor_eval): Likewise.
        (gimplify_target_expr): Likewise.
        (gimplify_cond_expr): Remove target handling.
        (gimplify_modify_expr): Don't clobber INIT_EXPR code here.
        (gimplify_expr): Clobber it here.
        (gimplify_modify_expr_rhs): Push assignment into COND_EXPR here.
        Do return slot optimization if we have an INIT_EXPR.

        PR tree-opt/24365
        * tree-inline.c (declare_return_variable): Also clear
        DECL_COMPLEX_GIMPLE_REG_P as needed in the modify_dest case.

        PR c++/16405
        * gimplify.c (gimplify_modify_expr_rhs): Re-enable *& handling.

        PR middle-end/22439
        * gimplify.c (gimplify_one_sizepos): Fix typo.

Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/cp/ChangeLog
    branches/gcc-4_1-branch/gcc/cp/cp-gimplify.c
    branches/gcc-4_1-branch/gcc/cp/typeck2.c
    branches/gcc-4_1-branch/gcc/doc/c-tree.texi
    branches/gcc-4_1-branch/gcc/gimplify.c
    branches/gcc-4_1-branch/gcc/testsuite/g++.dg/opt/temp1.C
    branches/gcc-4_1-branch/gcc/tree-inline.c
    branches/gcc-4_1-branch/gcc/tree.def


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0 Regression] incorrect codegen for conditional [SVO issue]

[jason at gcc dot gnu dot org]

------- Comment #12 from jason at gcc dot gnu dot org  2006-02-11 00:19 -------
Subject: Bug 25979

Author: jason
Date: Sat Feb 11 00:19:30 2006
New Revision: 110864

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110864
Log:
        PR c++/25979
        * tree.def: Elaborate on difference from MODIFY_EXPR.
        * doc/c-tree.texi (INIT_EXPR): Likewise.
        * cp/cp-gimplify.c (cp_gimplify_expr): Don't call
        cp_gimplify_init_expr for MODIFY_EXPRs.
        * cp/typeck2.c (split_nonconstant_init_1): Use INIT_EXPR.
        * gimplify.c (internal_get_tmp_var): Likewise.
        (gimplify_decl_expr, gimplify_init_ctor_eval): Likewise.
        (gimplify_target_expr): Likewise.
        (gimplify_cond_expr): Remove target handling.
        (gimplify_modify_expr): Don't clobber INIT_EXPR code here.
        (gimplify_expr): Clobber it here.
        (gimplify_modify_expr_rhs): Push assignment into COND_EXPR here.
        Do return slot optimization if we have an INIT_EXPR.

        PR middle-end/22439
        * gimplify.c (gimplify_one_sizepos): Fix typo.

Modified:
    branches/gcc-4_0-branch/gcc/ChangeLog
    branches/gcc-4_0-branch/gcc/cp/ChangeLog
    branches/gcc-4_0-branch/gcc/cp/cp-gimplify.c
    branches/gcc-4_0-branch/gcc/cp/typeck2.c
    branches/gcc-4_0-branch/gcc/doc/c-tree.texi
    branches/gcc-4_0-branch/gcc/gimplify.c
    branches/gcc-4_0-branch/gcc/tree.def


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979

[Bug c++/25979] [4.0 Regression] incorrect codegen for conditional [SVO issue]

[pinskia at gcc dot gnu dot org]

------- Comment #13 from pinskia at gcc dot gnu dot org  2006-02-11 00:51 -------
Fixed.


-- 

pinskia at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25979