https://issues.dlang.org/show_bug.cgi?id=23126

Paul Backus <snarwin+bugzilla@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
                 CC|                            |snarwin+bugzilla@gmail.com
           Severity|enhancement                 |normal

--- Comment #1 from Paul Backus <snarwin+bugzilla@gmail.com> ---
Reduced:

---
int fun() { return 123456; }

int divide(int dividend)
{
    return dividend == 0
        ? assert(0)
        : dividend / dividend;
}

void main()
{
    fun();
    int c = divide(1);
    assert(c == 1);
}
---

As of DMD 2.100.0, with -checkaction=context, this produces the following output:

---
core.exception.AssertError@bug.d(14): 123456 != 1
---

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https://issues.dlang.org/show_bug.cgi?id=23126

Iain Buclaw <ibuclaw@gdcproject.org> changed:

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

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https://issues.dlang.org/show_bug.cgi?id=23126

--- Comment #2 from kdevel <kdevel@vogtner.de> ---
(In reply to kdevel from comment #0)
> $ dmd div.d
> $ ./div 1 2
> 1 / 2 = 2

dmd 2.100.2: bad

$ ./div 1 2
1 / 2 = 2

dmd 2.101.1 and newer: good

$ ./div 1 2
1 / 2 = 0


(In reply to Paul Backus from comment #1)
> Reduced:
>
> As of DMD 2.100.0, with -checkaction=context, this produces the following output:

Works since dmd 2.101.1.

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https://issues.dlang.org/show_bug.cgi?id=23126

Siarhei Siamashka <siarhei.siamashka@hotmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |siarhei.siamashka@hotmail.c
                   |                            |om

--- Comment #3 from Siarhei Siamashka <siarhei.siamashka@hotmail.com> ---
(In reply to kdevel from comment #2)
> Works since dmd 2.101.1.

Does the DMD test suite have a test for it? To ensure that this problem does not re-appear again in the future.

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https://issues.dlang.org/show_bug.cgi?id=23126

--- Comment #4 from kdevel <kdevel@vogtner.de> ---
(In reply to Siarhei Siamashka from comment #3)
> (In reply to kdevel from comment #2)
> > Works since dmd 2.101.1.
> 
> Does the DMD test suite have a test for it? To ensure that this problem does not re-appear again in the future.
Simple question, not easy to answer. For now more than two hours I am trying to bisect dmd between v2.100.2 and v2.101.1 to no avail. I have stopped when git asked me to compile a commit of 2016

[e8ab5ca21f3010bb40509ca7aaf575440886795b] Merge pull request #1639 from WalterBright/rm-PostBlitType

$ make -f posix.mak
../dmd/src/dmd -conf= -c -o- -Isrc -Iimport -Hfimport/core/sync/barrier.di
src/core/sync/barrier.d
make: ../dmd/src/dmd: Command not found
make: *** [import/core/sync/barrier.di] Error 127

which fails. I could not git bisect skip this often enough in a reasonable amount of time.

dmd 2.105.3 could not compile the old compiler:

[...]
(DC) COMMON

The following operation failed:
Name: common
Sources:
 -> /tmp/k/dmd/src/dmd/common/bitfields.d
 -> /tmp/k/dmd/src/dmd/common/file.d
 -> /tmp/k/dmd/src/dmd/common/int128.d
 -> /tmp/k/dmd/src/dmd/common/outbuffer.d
 -> /tmp/k/dmd/src/dmd/common/string.d

Targets:
 -> /tmp/k/dmd/generated/linux/release/64/common.o

Command: [...]dmd2/linux/bin64/dmd -c -of/tmp/k/dmd/generated/linux/release/64/common.o -version=MARS -w -de -fPIC -m64 -J/tmp/k/dmd/generated/linux/release/64 -I/tmp/k/dmd/src -dip25 -g -color=on src/dmd/common/bitfields.d src/dmd/common/file.d src/dmd/common/int128.d src/dmd/common/outbuffer.d src/dmd/common/string.d

-----------------------------------------------------------
Deprecation: `-dip25` no longer has any effect

make[1]: *** [dmd] Error 1

Therefor I used dmd 2.098.1 as HOST_DMD

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https://issues.dlang.org/show_bug.cgi?id=23126

Basile-z <b2.temp@gmx.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |b2.temp@gmx.com

--- Comment #5 from Basile-z <b2.temp@gmx.com> ---
> Simple question, not easy to answer.

Use Vladimir `digger --bisect` it will be easier:

https://github.com/CyberShadow/Digger

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https://issues.dlang.org/show_bug.cgi?id=23126

--- Comment #6 from kdevel <kdevel@vogtner.de> ---
(In reply to kdevel from comment #4)
> (In reply to Siarhei Siamashka from comment #3)
> > (In reply to kdevel from comment #2)
> > > Works since dmd 2.101.1.
> > 
> > Does the DMD test suite have a test for it? To ensure that this problem does not re-appear again in the future.
> Simple question, not easy to answer.
It was fixed between v2.101.0 and v2.101.1 (named "bad" commit because of
inverted roles):

d836c8bcec16205644e3aacf15f1a1cf7d655dd5 is the first bad commit
commit d836c8bcec16205644e3aacf15f1a1cf7d655dd5
Author: mhh <maxhaton@gmail.com>
Date:   Thu Dec 15 06:15:28 2022 +0000

    Fix Issue 23549, 22587 - Lower certain noreturn expressions to a comma
expression rather than a cast.

    This avoids a backend segfault.

    GDC already does this lowering so it may have to be made optional via a
frontend parameter.

:040000 040000 29998096bd165299cd08f15f32ab2dd047461bd8 70e6048af4184c4d4edb72add21fcbb0dac57957 M      compiler

--