[Bug target/107131] New: wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[Bug target/107131] New: wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

            Bug ID: 107131
           Summary: wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          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 53655
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53655&action=edit
reduced testcase

Output:
$ x86_64-pc-linux-gnu-gcc -Os -fno-ipa-vrp -fno-tree-bit-ccp testcase.c
-Wno-psabi
$ ./a.out 
Aborted

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r13-3023-20221003092645-g31d7c8bc263-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/13.0.0/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-r13-3023-20221003092645-g31d7c8bc263-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.0.0 20221003 (experimental) (GCC)

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2022-10-03
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
            Summary|wrong code with -Os         |[11/12 Regression] wrong
                   |-fno-ipa-vrp                |code with -Os -fno-ipa-vrp
                   |-fno-tree-bit-ccp           |-fno-tree-bit-ccp
     Ever confirmed|0                           |1

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
It's there since the introduction of __builtin_shufflevector
(r12-1128-gef8176e0fac935c0).

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note there is a missed optimization here (unrelated to the wrong code):
  _32 = o_13(D) == 0;
  _35 = (long int) _32;
  _36 = -_35;
  _109 = (long long unsigned int) _36;
  _102 = _109 > 10439075533421201520;

This should just be:

  _32 = o_13(D) == 0;
  _ = (long long unsigned int) _32;
  _109 = -_35;

Let me file that as a seperate bug.

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2) 
> Let me file that as a seperate bug.

Created PR 107137.

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[11/12 Regression] wrong    |[11/12/13 Regression] wrong
                   |code with -Os -fno-ipa-vrp  |code with -Os -fno-ipa-vrp
                   |-fno-tree-bit-ccp           |-fno-tree-bit-ccp
   Target Milestone|---                         |11.4

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note __builtin_shufflevector might just be the point we were able to produce
the
input GIMPLE required to trigger the previously latent issue.

The difference between -O (working) and -Os (failing) starts at RTL expansion
only.

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This doesn't fail on the trunk anymore since
r13-3217-gc4d15dddf6b9eacb36f535807ad2ee364af46e04

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #6 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:add71b95dd27d73d64eee0a9c8f748672b7050f5

commit r13-5139-gadd71b95dd27d73d64eee0a9c8f748672b7050f5
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Jan 13 11:13:22 2023 +0100

    testsuite: Add testcase for PR that went latent in GCC 13 [PR107131]

    The following testcase is probably latent since r13-3217-gc4d15dddf6b9e.
    Adding testcase so that it doesn't silently reappear.

    2023-01-13  Jakub Jelinek  <jakub@redhat.com>

            PR target/107131
            * gcc.dg/pr107131.c: New test.

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
If I change the testcase to:
/* PR target/107131 */
/* { dg-do run } */
/* { dg-options "-Os -fno-ipa-vrp -fno-tree-bit-ccp -Wno-psabi" } */

typedef unsigned char C;
typedef unsigned long long __attribute__((__vector_size__ (32))) U;
typedef unsigned long long __attribute__((__vector_size__ (64))) V;

static __attribute__((__noclone__)) C
foo (C o, U x, U y, U z)
{
  V w = { x[0], x[1], x[2], x[3], 0, 0, 0, 0 };
  V a = __builtin_shuffle (w, w, (V) {3, 1, 3, 0, 0, 1, 1, 3});
  V b = (V) { } >= o;
  V c = b <= (V)(b >= (V) { 0, 0, 0, 0, 0, 0x90DF0BE3990AC871ULL });
  U d = __builtin_shuffle (y, z, (U) {3, 1, 4, 5});
  V e = a + c;
  U f = ((union { V v; U u[2]; }) e).u[1] + d;
  return ((union { U u; C c[32]; }) f).c[9];
}

int
main ()
{
  if (__SIZEOF_LONG_LONG__ != 8 || __CHAR_BIT__ != 8)
    return 0;
  C x = foo (0, (U) { }, (U) { }, (U) { });
  if (x != 0xff)
    __builtin_abort();  
  return 0;
}
then it started with r12-1055-gb6bdd7a4cb41ee057f2d064fffcb00f23ce6b497
already,
but similarly to the other testcase got fixed or made latent with
r13-3217.

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com,
                   |                            |uros at gcc dot gnu.org

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think the problem happens during combine.  Parts of the vector code related
to:
  V b = (V) { } >= o;
  V c = b <= (V)(b >= (V) { 0, 0, 0, 0, 0, 0x90DF0BE3990AC871ULL });
- in particular the scalar c[5] computation, i.e.
unsigned long long b = 0 >= o ? -1ULL : 0ULL;
unsigned long long c = b <= (b >= 0x90DF0BE3990AC871ULL ? -1ULL : 0ULL) ? -1ULL
: 0ULL;
evaluates to 0 rather than -1 that it should when o is 0.

This boils down to:
__attribute__((noipa)) unsigned long long
foo (unsigned char o)
{
  unsigned long long t1 = -(long long) (o == 0);
  unsigned long long t2 = -(long long) (t1 > 10439075533421201520ULL);
  unsigned long long t3 = -(long long) (t1 <= t2);
  return t3;
}

int
main ()
{
  if (foo (0) != -1ULL)
    __builtin_abort ();
  return 0;
}
at -O2 or -Os, which was miscompiled starting with r12-303-g86403f4e6e5f7216
and got fixed with r13-3530-g0e36a9c6915c713d30.
No idea why this is marked as 11 regression though...

So, do we need to backport PR107172 change to 12 branch?

[Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #9 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:254cf9552ffb1693f0bc74f6d25601dafafbc144

commit r13-5150-g254cf9552ffb1693f0bc74f6d25601dafafbc144
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Jan 13 17:37:52 2023 +0100

    testsuite: Add another testcase from PR107131

    This one is hand reduced to problematic code from optimized dump
    that used to be miscompiled during combine starting with
    r12-303 and fixed with r13-3530 aka PR107172 fix.

    2023-01-13  Jakub Jelinek  <jakub@redhat.com>

            PR target/107131
            * gcc.c-torture/execute/pr107131.c: New test.

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[11/12/13 Regression] wrong |[11/12 Regression] wrong
                   |code with -Os -fno-ipa-vrp  |code with -Os -fno-ipa-vrp
                   |-fno-tree-bit-ccp           |-fno-tree-bit-ccp

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Anyway, clearly fixed on the trunk + testsuite covered in case it reappears.

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #8)
> I think the problem happens during combine.  Parts of the vector code
> related to:
>   V b = (V) { } >= o;
>   V c = b <= (V)(b >= (V) { 0, 0, 0, 0, 0, 0x90DF0BE3990AC871ULL });
> - in particular the scalar c[5] computation, i.e.
> unsigned long long b = 0 >= o ? -1ULL : 0ULL;
> unsigned long long c = b <= (b >= 0x90DF0BE3990AC871ULL ? -1ULL : 0ULL) ?
> -1ULL : 0ULL;
> evaluates to 0 rather than -1 that it should when o is 0.
> 
> This boils down to:
> __attribute__((noipa)) unsigned long long
> foo (unsigned char o)
> {
>   unsigned long long t1 = -(long long) (o == 0);
>   unsigned long long t2 = -(long long) (t1 > 10439075533421201520ULL);
>   unsigned long long t3 = -(long long) (t1 <= t2);
>   return t3;
> }
> 
> int
> main ()
> {
>   if (foo (0) != -1ULL)
>     __builtin_abort ();
>   return 0;
> }
> at -O2 or -Os, which was miscompiled starting with r12-303-g86403f4e6e5f7216
> and got fixed with r13-3530-g0e36a9c6915c713d30.
> No idea why this is marked as 11 regression though...
> 
> So, do we need to backport PR107172 change to 12 branch?

Yes.  Testing that now.

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #11)
> (In reply to Jakub Jelinek from comment #8)
> > I think the problem happens during combine.  Parts of the vector code
> > related to:
> >   V b = (V) { } >= o;
> >   V c = b <= (V)(b >= (V) { 0, 0, 0, 0, 0, 0x90DF0BE3990AC871ULL });
> > - in particular the scalar c[5] computation, i.e.
> > unsigned long long b = 0 >= o ? -1ULL : 0ULL;
> > unsigned long long c = b <= (b >= 0x90DF0BE3990AC871ULL ? -1ULL : 0ULL) ?
> > -1ULL : 0ULL;
> > evaluates to 0 rather than -1 that it should when o is 0.
> > 
> > This boils down to:
> > __attribute__((noipa)) unsigned long long
> > foo (unsigned char o)
> > {
> >   unsigned long long t1 = -(long long) (o == 0);
> >   unsigned long long t2 = -(long long) (t1 > 10439075533421201520ULL);
> >   unsigned long long t3 = -(long long) (t1 <= t2);
> >   return t3;
> > }
> > 
> > int
> > main ()
> > {
> >   if (foo (0) != -1ULL)
> >     __builtin_abort ();
> >   return 0;
> > }
> > at -O2 or -Os, which was miscompiled starting with r12-303-g86403f4e6e5f7216
> > and got fixed with r13-3530-g0e36a9c6915c713d30.
> > No idea why this is marked as 11 regression though...
> > 
> > So, do we need to backport PR107172 change to 12 branch?
> 
> Yes.  Testing that now.

Not.  Not picking cleanly.

[Bug target/107131] [11/12 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.4                        |11.5

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 11.4 is being released, retargeting bugs to GCC 11.5.