[Bug tree-optimization/104604] New: wrong code with -O2 -fconserve-stack --param=vrp1-mode=ranger

[Bug tree-optimization/104604] New: wrong code with -O2 -fconserve-stack --param=vrp1-mode=ranger

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

            Bug ID: 104604
           Summary: wrong code with -O2 -fconserve-stack
                    --param=vrp1-mode=ranger
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 52479
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52479&action=edit
reduced testcase

Output:
$ x86_64-pc-linux-gnu-gcc -O2 -fconserve-stack --param=vrp1-mode=ranger
testcase.c -Wno-psabi
$ ./a.out 
Aborted

The value of x[] is {3, 3, 3, 3, ... }
It seems "i /= c;" got optimised out.

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r12-7293-20220218075854-gfe79d652c96-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --with-cloog --with-ppl --with-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r12-7293-20220218075854-gfe79d652c96-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.1 20220218 (experimental) (GCC)

[Bug tree-optimization/104604] [12 Regression]wrong code with -O2 VRP Complex integer division issue

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |11.2.0
   Target Milestone|---                         |12.0
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
            Summary|wrong code with -O2         |[12 Regression]wrong code
                   |-fconserve-stack            |with -O2  VRP Complex
                   |--param=vrp1-mode=ranger    |integer division issue
   Last reconfirmed|                            |2022-02-19

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, reduced testcase which shows the problem even at just -O2:
typedef unsigned char u8;
u8 g;

 __attribute__((noipa))
u8 foo (_Complex unsigned c)
{
 _Complex unsigned t = 3;
  t /= c;
  u8 v = g;
  return v + t;
}

int
main (void)
{
    u8 x = foo (7);
    if (x)
        __builtin_abort ();
    return 0;
}

[Bug tree-optimization/104604] [12 Regression]wrong code with -O2 VRP Complex integer division issue

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

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

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

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
The EVRP dump with -details isn't very useful, we just see the
folding/substitution phase:

Folding statement: t_5 = __complex__ (3, 0) / c_4(D);
Not folded
Folding statement: v_7 = g;
Not folded
Folding statement: _1 = REALPART_EXPR <t_5>;
Queued stmt for removal.  Folds to: 3

and that looks obviously wrong.

[Bug tree-optimization/104604] [12 Regression]wrong code with -O2 VRP Complex integer division issue since r12-3328

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-bisection             |
                 CC|                            |jakub at gcc dot gnu.org
            Summary|[12 Regression]wrong code   |[12 Regression]wrong code
                   |with -O2  VRP Complex       |with -O2  VRP Complex
                   |integer division issue      |integer division issue
                   |                            |since r12-3328

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r12-3328-gbccf4b88e184e925ee2d7931e4cf09704f1c3932

[Bug tree-optimization/104604] [12 Regression]wrong code with -O2 VRP Complex integer division issue since r12-3328

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

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

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

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 52483
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52483&action=edit
gcc12-pr104604.patch

Untested fix.

[Bug tree-optimization/104604] [12 Regression]wrong code with -O2 VRP Complex integer division issue since r12-3328

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:d44dc131f48254fccc69ec4178fec030e0e2761d

commit r12-7324-gd44dc131f48254fccc69ec4178fec030e0e2761d
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Feb 22 10:43:13 2022 +0100

    ranger: Fix up REALPART_EXPR/IMAGPART_EXPR handling [PR104604]

    The following testcase is miscompiled since r12-3328.
    That change assumed that if rhs1 of a GIMPLE_ASSIGN is COMPLEX_CST, then
    that is the value of the lhs of the stmt, but that is not the case always,
    only if it is a GIMPLE_SINGLE_RHS stmt.  If it is e.g.
    GIMPLE_UNARY_RHS or GIMPLE_BINARY_RHS (the latter happens in the testcase),
    then it can be e.g.
    __complex__ (3, 0) / var
    and the REALPART_EXPR of that isn't 3, but the realpart of the division.
    I assume once the ranger can do complex numbers adjust_*part_expr will just
    fetch one or the other range from a underlying complex range, but until
    then, we should limit this to what r12-3328 meant to do.

    2022-02-22  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/104604
            * gimple-range-fold.cc (adjust_imagpart_expr,
adjust_realpart_expr):
            Only check if gimple_assign_rhs1 is COMPLEX_CST if
            gimple_assign_rhs_code is COMPLEX_CST.

            * gcc.c-torture/execute/pr104604.c: New test.

[Bug tree-optimization/104604] [12 Regression]wrong code with -O2 VRP Complex integer division issue since r12-3328

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104604

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

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

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.