[Bug ada/98230] New: Bug in Type'Modulus during a loop whose range is computed by a variable

[Bug ada/98230] New: Bug in Type'Modulus during a loop whose range is computed by a variable

[adam at vany dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

            Bug ID: 98230
           Summary: Bug in Type'Modulus during a loop whose range is
                    computed by a variable
           Product: gcc
           Version: 8.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: adam at vany dot ca
  Target Milestone: ---

Created attachment 49732
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49732&action=edit
Source code to reproduce

The T'Modulus of a type appears to change during a loop with a computed range.

The bug does not reproduce if the loop has a fixed range (range 1 .. 30 instead
of range 1 .. Max).  It also does not reproduce if T'Mod is not called during
the loop.


==== Output
N:  1 Modulus:     3 Mod: 1
N:  2 Modulus:     3 Mod: 2
N:  3 Modulus:     3 Mod: 3
N:  4 Modulus:     3 Mod: 4
N:  5 Modulus:     3 Mod: 5
N:  6 Modulus:     3 Mod: 6
N:  7 Modulus:     3 Mod: 7
N:  8 Modulus:     3 Mod: 8
N:  9 Modulus:     3 Mod: 9
N:  10 Modulus:    03 Mod: 10
N:  11 Modulus:    13 Mod: 11
N:  12 Modulus:    23 Mod: 12
N:  13 Modulus:    33 Mod: 13
N:  14 Modulus:    43 Mod: 14
N:  15 Modulus:    53 Mod: 15
N:  16 Modulus:    63 Mod: 16
N:  17 Modulus:    73 Mod: 17
N:  18 Modulus:    83 Mod: 18
N:  19 Modulus:    93 Mod: 19
N:  20 Modulus:    03 Mod: 20
N:  21 Modulus:    13 Mod: 21
N:  22 Modulus:    23 Mod: 22
N:  23 Modulus:    33 Mod: 23
N:  24 Modulus:    43 Mod: 24
N:  25 Modulus:    53 Mod: 25
N:  26 Modulus:    63 Mod: 26
N:  27 Modulus:    73 Mod: 27
N:  28 Modulus:    83 Mod: 28
N:  29 Modulus:    93 Mod: 29
N:  30 Modulus:    03 Mod: 30

=== Expected output
Modulus should not change, it should always be 3, Mod: should always stay in
the range 0-3.

If the loop is change to 1 .. 30, instead of 1 .. Max, it works as expected.

[Bug ada/98230] Bug in Type'Modulus during a loop whose range is computed by a variable

[adam at vany dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

--- Comment #1 from Adam Van Ymeren <adam at vany dot ca> ---
Forgot some details

=== output of gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 8.3.0-6'
--with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 8.3.0 (Debian 8.3.0-6)

[Bug ada/98230] Bug in Type'Modulus during a loop whose range is computed by a variable

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2020-12-10
     Ever confirmed|0                           |1
                 CC|                            |ebotcazou at gcc dot gnu.org

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Rather curious indeed.

[Bug ada/98230] Bug in Type'Modulus during a loop whose range is computed by a variable

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

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

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

--- Comment #3 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Investigating.

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |8.5
            Summary|Incorrect Type'Mod during a |incorrect Type'Mod during a
                   |loop whose range is         |loop whose range is
                   |computed by a variable      |computed by a variable

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Eric Botcazou <ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:779bf1823ced0814803d2be7f7ded0317e70140c

commit r11-5920-g779bf1823ced0814803d2be7f7ded0317e70140c
Author: Ed Schonberg <schonberg@adacore.com>
Date:   Thu Dec 10 22:26:57 2020 +0100

    Fix PR ada/98230

    It's a rather curious malfunction of the 'Mod attribute applied to the
    variable of a loop whose upper bound is dynamic.

    gcc/ada/ChangeLog:
            PR ada/98230
            * exp_attr.adb (Expand_N_Attribute_Reference, case Mod): Use base
            type of argument to obtain static bound and required size.

    gcc/testsuite/ChangeLog:
            * gnat.dg/modular6.adb: New test.

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Eric Botcazou
<ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:bc7d2977d108ed00c30c9f21d5701f28ffb50f29

commit r10-9137-gbc7d2977d108ed00c30c9f21d5701f28ffb50f29
Author: Ed Schonberg <schonberg@adacore.com>
Date:   Thu Dec 10 22:26:57 2020 +0100

    Fix PR ada/98230

    It's a rather curious malfunction of the 'Mod attribute applied to the
    variable of a loop whose upper bound is dynamic.

    gcc/ada/ChangeLog:
            PR ada/98230
            * exp_attr.adb (Expand_N_Attribute_Reference, case Mod): Use base
            type of argument to obtain static bound and required size.

    gcc/testsuite/ChangeLog:
            * gnat.dg/modular6.adb: New test.

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Eric Botcazou
<ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:da6e672dc9bbedb993a5fea498954f0ca861b7ec

commit r9-9107-gda6e672dc9bbedb993a5fea498954f0ca861b7ec
Author: Ed Schonberg <schonberg@adacore.com>
Date:   Thu Dec 10 22:26:57 2020 +0100

    Fix PR ada/98230

    It's a rather curious malfunction of the 'Mod attribute applied to the
    variable of a loop whose upper bound is dynamic.

    gcc/ada/ChangeLog:
            PR ada/98230
            * exp_attr.adb (Expand_N_Attribute_Reference, case Mod): Use base
            type of argument to obtain static bound and required size.

    gcc/testsuite/ChangeLog:
            * gnat.dg/modular6.adb: New test.

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-8 branch has been updated by Eric Botcazou
<ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:87c40733898283f0d1e48bcbf8055c2718064e77

commit r8-10673-g87c40733898283f0d1e48bcbf8055c2718064e77
Author: Ed Schonberg <schonberg@adacore.com>
Date:   Thu Dec 10 22:26:57 2020 +0100

    Fix PR ada/98230

    It's a rather curious malfunction of the 'Mod attribute applied to the
    variable of a loop whose upper bound is dynamic.

    gcc/ada/ChangeLog:
            PR ada/98230
            * exp_attr.adb (Expand_N_Attribute_Reference, case Mod): Use base
            type of argument to obtain static bound and required size.

    gcc/testsuite/ChangeLog:
            * gnat.dg/modular6.adb: New test.

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

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

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

--- Comment #8 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Fixed on all branches.

[Bug ada/98230] incorrect Type'Mod during a loop whose range is computed by a variable

[adam at vany dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98230

--- Comment #9 from Adam Van Ymeren <adam at vany dot ca> ---
Awesome thanks!