[Bug tree-optimization/107855] New: gcc.dg/vect/vect-ifcvt-18.c FAILs

[Bug tree-optimization/107855] New: gcc.dg/vect/vect-ifcvt-18.c FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

            Bug ID: 107855
           Summary: gcc.dg/vect/vect-ifcvt-18.c FAILs
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: lingling.kong7 at gmail dot com
  Target Milestone: ---
            Target: i386-pc-solaris2.12, x86_64-pc-linux-gnu

Since it was introduced, the new gcc.dg/vect/vect-ifcvt-18.c test FAILs on
Solaris/x86:

* 32-bit:

FAIL: gcc.dg/vect/vect-ifcvt-18.c -flto -ffat-lto-objects  scan-tree-dump vect
"vectorized 3 loops"
FAIL: gcc.dg/vect/vect-ifcvt-18.c -flto -ffat-lto-objects execution test
FAIL: gcc.dg/vect/vect-ifcvt-18.c execution test
FAIL: gcc.dg/vect/vect-ifcvt-18.c scan-tree-dump vect "vectorized 3 loops"

* 64-bit:

FAIL: gcc.dg/vect/vect-ifcvt-18.c -flto -ffat-lto-objects  scan-tree-dump vect
"vectorized 3 loops"
FAIL: gcc.dg/vect/vect-ifcvt-18.c scan-tree-dump vect "vectorized 3 loops"

There are also several gcc-testresults reports for Linux/x86_64.

The 32-bit execution test hits abort in l.34 (nothing useful to be learned
from gdb: res? all optimized out.  I'm also including the 32-bit dump.

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

--- Comment #1 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 53958
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53958&action=edit
32-bit i386-pc-solaris2.11 vect-ifcvt-18.c.172t.vect

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Can you attach the ifcvt dump as well?  The issue seems to be that only the
first loop is if-converted, so floats are not handled at all (only a single
loop is vectorized).

Not sure about the runtime FAIL with 32bit - does that also happen with -O0?

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

--- Comment #3 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 53959
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53959&action=edit
32-bit i386-pc-solaris2.11 vect-ifcvt-18.c.171t.ifcvt

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

--- Comment #4 from Rainer Orth <ro at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> Can you attach the ifcvt dump as well?  The issue seems to be that only the
> first loop is if-converted, so floats are not handled at all (only a single
> loop is vectorized).

Sure, done.

> Not sure about the runtime FAIL with 32bit - does that also happen with -O0?

No, the test runs successfully then.

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.0                        |13.2

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.1 is being released, retargeting bugs to GCC 13.2.

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-05-13
                 CC|                            |xry111 at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #6 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Hmm, the test contains

"/* { dg-additional-options "-Ofast -mavx" { target avx_runtime } } */"

So it passes on AVX capable native builds, but fails otherwise.

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.2                        |13.3

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.2 is being released, retargeting bugs to GCC 13.3.

[Bug tree-optimization/107855] gcc.dg/vect/vect-ifcvt-18.c FAILs

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107855

--- Comment #8 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> --- Comment #6 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
> Hmm, the test contains
>
> "/* { dg-additional-options "-Ofast -mavx" { target avx_runtime } } */"
>
> So it passes on AVX capable native builds, but fails otherwise.

I can reproduce things in a VM now: when it doesn't have avx support,
the test is compiled with -msse2 only and FAILs both for the dump and
execution:

FAIL: gcc.dg/vect/vect-ifcvt-18.c -flto -ffat-lto-objects  scan-tree-dump vect
"vectorized 3 loops"
FAIL: gcc.dg/vect/vect-ifcvt-18.c -flto -ffat-lto-objects execution test
FAIL: gcc.dg/vect/vect-ifcvt-18.c execution test
FAIL: gcc.dg/vect/vect-ifcvt-18.c scan-tree-dump vect "vectorized 3 loops"

The test aborts here:

Thread 2 received signal SIGABRT, Aborted.

#0  0xfe26e385 in __lwp_sigqueue () from /lib/libc.so.1
#1  0xfe2660ef in thr_kill () from /lib/libc.so.1
#2  0xfe19db82 in raise () from /lib/libc.so.1
#3  0xfe16b1f4 in abort () from /lib/libc.so.1
#4  0x08050d58 in main ()
    at
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:34

and the dump shows

/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:28:17:
note:  === analyze_loop_nest ===
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:28:17:
note:   === vect_analyze_loop_form ===
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:28:17:
note:   using as main loop exit: 13 -> 14 [AUX: 0]
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:28:17:
missed:   not vectorized: unsupported control flow in loop.
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:28:17:
missed:  bad loop form.
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/vect-ifcvt-18.c:28:17:
missed: couldn't vectorize loop

When I add avx support to the VM, the test PASSes.

It seems the test is missing some requirement here.