[r12-4397 Regression] FAIL: gcc.dg/guality/pr54200.c -Og -DPREVENT_OPTIMIZATION line 20 z == 3 on Linux/x86_64

[r12-4397 Regression] FAIL: gcc.dg/guality/pr54200.c -Og -DPREVENT_OPTIMIZATION line 20 z == 3 on Linux/x86_64

[sunil.k.pandey]

On Linux/x86_64,

4cb52980e5d5fb64a393d385923da1b51ab34606 is the first bad commit
commit 4cb52980e5d5fb64a393d385923da1b51ab34606
Author: Martin Liska <mliska@suse.cz>
Date:   Tue Oct 12 14:31:50 2021 +0200

    Eliminate AUTODETECT_VALUE usage in options.

caused

FAIL: gcc.dg/guality/pr54200.c  -Og -DPREVENT_OPTIMIZATION  line 20 z == 3

with GCC configured with

../../gcc/configure --prefix=/local/skpandey/gccwork/toolwork/gcc-bisect-master/master/r12-4397/usr --enable-clocale=gnu --with-system-zlib --with-demangler-in-ld --with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl --enable-libmpx x86_64-linux --disable-bootstrap

To reproduce:

$ cd {build_dir}/gcc && make check RUNTESTFLAGS="guality.exp=gcc.dg/guality/pr54200.c --target_board='unix{-m64}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="guality.exp=gcc.dg/guality/pr54200.c --target_board='unix{-m64\ -march=cascadelake}'"

(Please do not reply to this email, for question about this report, contact me at skpgkp2 at gmail dot com)

Re: [r12-4397 Regression] FAIL: gcc.dg/guality/pr54200.c -Og -DPREVENT_OPTIMIZATION line 20 z == 3 on Linux/x86_64

[Martin Liška]

On 10/14/21 21:16, sunil.k.pandey wrote:
> FAIL: gcc.dg/guality/pr54200.c  -Og -DPREVENT_OPTIMIZATION  line 20 z == 3

Hello.

I've just verified the assembly is identical before and after the revision.
So it must be a false positive.

Cheers,
Martin

Re: [r12-4397 Regression] FAIL: gcc.dg/guality/pr54200.c -Og -DPREVENT_OPTIMIZATION line 20 z == 3 on Linux/x86_64

[H.J. Lu]

On Fri, Oct 15, 2021 at 2:00 AM Martin Liška <mliska@suse.cz> wrote:
>
> On 10/14/21 21:16, sunil.k.pandey wrote:
> > FAIL: gcc.dg/guality/pr54200.c  -Og -DPREVENT_OPTIMIZATION  line 20 z == 3
>
> Hello.
>
> I've just verified the assembly is identical before and after the revision.
> So it must be a false positive.
>
> Cheers,
> Martin

I saw

Breakpoint 1, foo (z=3, x=<optimized out>, b=1) at
/export/gnu/import/git/gitlab/x86-gcc/gcc/testsuite/gcc.dg/guality/pr54200.c:20^M
20            return a; /* { dg-final { gdb-test . "z" "3" { xfail {
aarch64*-*-* && { no-opts "-O0" "-Og" } } } } } */^M
$1 =  [uninitialized] 3^M
$2 = 3^M
A debugging session is active.^M
^M
        Inferior 1 [process 4053185] will be killed.^M
^M
Quit anyway? (y or n) [answered Y; input not from terminal]^M
 [uninitialized] 3 != 3
FAIL: gcc.dg/guality/pr54200.c  -Og -DPREVENT_OPTIMIZATION  line 20 z == 3

I don't know where [uninitialized] came from.  I can't reproduce it
when I run gdb by hand.

-- 
H.J.