[Bug tree-optimization/97075] New: [11 regression] powerpc64 vector tests fails after r11-3230

[Bug tree-optimization/97075] New: [11 regression] powerpc64 vector tests fails after r11-3230

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

            Bug ID: 97075
           Summary: [11 regression] powerpc64 vector tests fails after
                    r11-3230
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at gcc dot gnu.org
  Target Milestone: ---

g:052204fac580b21c967e57e6285d99a9828b8fac, r11-3230

FAIL: gcc.target/powerpc/p9-vec-length-epil-7.c scan-assembler-times
\\mstxvl\\M 10
FAIL: gcc.target/powerpc/p9-vec-length-full-6.c scan-assembler-not \\mlxvx\\M
FAIL: gcc.target/powerpc/p9-vec-length-full-6.c scan-assembler-not \\mstxvx\\M
FAIL: gcc.target/powerpc/p9-vec-length-full-6.c scan-assembler-times \\mlxvl\\M
16
FAIL: gcc.target/powerpc/p9-vec-length-full-6.c scan-assembler-times
\\mstxvl\\M 16

For the second test case here is a diff of the assembler:

seurer@makalu-lp1:~/gcc/git/build/gcc-test$ diff
p9-vec-length-epil-7.s.r11-3229 p9-vec-length-epil-7.s.r11-3230
322,323c322,323
<       li 6,28
<       addis 7,2,.LC8@toc@ha
---
> 	li 7,28
> 	addis 8,2,.LC8@toc@ha
325d324
<       addis 10,2,.LANCHOR0@toc@ha
327,330c326,328
<       li 8,0
<       mtctr 6
<       addi 7,7,.LC8@toc@l
<       addi 10,10,.LANCHOR0@toc@l
---
> 	li 10,0
> 	mtctr 7
> 	addi 8,8,.LC8@toc@l
333,335c331,333
<       lxv 32,0(7)
<       addis 7,2,.LANCHOR0+904@toc@ha
<       std 8,.LANCHOR0+904@toc@l(7)
---
> 	lxv 32,0(8)
> 	addis 8,2,.LANCHOR0+904@toc@ha
> 	std 10,.LANCHOR0+904@toc@l(8)
343,349c341,343
<       addis 7,2,.LC9@toc@ha
<       li 8,8
<       addi 9,10,1360
<       addi 7,7,.LC9@toc@l
<       sldi 10,8,56
<       lxv 0,0(7)
<       stxvl 0,9,10
---
> 	li 9,57
> 	addis 10,2,.LANCHOR0+1360@toc@ha
> 	std 9,.LANCHOR0+1360@toc@l(10)
368,369c362,363
<       li 6,28
<       addis 7,2,.LC8@toc@ha
---
> 	li 7,28
> 	addis 8,2,.LC8@toc@ha
371d364
<       addis 10,2,.LANCHOR0@toc@ha
373,376c366,368
<       li 8,0
<       mtctr 6
<       addi 7,7,.LC8@toc@l
<       addi 10,10,.LANCHOR0@toc@l
---
> 	li 10,0
> 	mtctr 7
> 	addi 8,8,.LC8@toc@l
379,381c371,373
<       lxv 32,0(7)
<       addis 7,2,.LANCHOR0+1416@toc@ha
<       std 8,.LANCHOR0+1416@toc@l(7)
---
> 	lxv 32,0(8)
> 	addis 8,2,.LANCHOR0+1416@toc@ha
> 	std 10,.LANCHOR0+1416@toc@l(8)
389,395c381,383
<       addis 7,2,.LC9@toc@ha
<       li 8,8
<       addi 9,10,1872
<       addi 7,7,.LC9@toc@l
<       sldi 10,8,56
<       lxv 0,0(7)
<       stxvl 0,9,10
---
> 	li 9,57
> 	addis 10,2,.LANCHOR0+1872@toc@ha
> 	std 9,.LANCHOR0+1872@toc@l(10)
414,415c402,403
<       addis 6,2,.LC10@toc@ha
<       addis 7,2,.LC11@toc@ha
---
> 	addis 6,2,.LC9@toc@ha
> 	addis 7,2,.LC10@toc@ha
421,422c409,410
<       addi 6,6,.LC10@toc@l
<       addi 7,7,.LC11@toc@l
---
> 	addi 6,6,.LC9@toc@l
> 	addi 7,7,.LC10@toc@l
441c429
<       addis 7,2,.LC12@toc@ha
---
> 	addis 7,2,.LC11@toc@ha
444c432
<       addi 7,7,.LC12@toc@l
---
> 	addi 7,7,.LC11@toc@l
466,469c454,456
<       addis 7,2,.LC13@toc@ha
<       li 6,28
<       addis 8,2,.LC14@toc@ha
<       addis 10,2,.LANCHOR0@toc@ha
---
> 	addis 8,2,.LC12@toc@ha
> 	li 7,28
> 	addis 10,2,.LC13@toc@ha
472,475c459,461
<       addi 7,7,.LC13@toc@l
<       mtctr 6
<       addi 8,8,.LC14@toc@l
<       addi 10,10,.LANCHOR0@toc@l
---
> 	addi 8,8,.LC12@toc@l
> 	mtctr 7
> 	addi 10,10,.LC13@toc@l
477,480c463,466
<       lxv 0,0(7)
<       lxv 11,0(8)
<       addis 8,2,.LANCHOR0+2184@toc@ha
<       stfd 12,.LANCHOR0+2184@toc@l(8)
---
> 	lxv 0,0(8)
> 	lxv 11,0(10)
> 	addis 10,2,.LANCHOR0+2184@toc@ha
> 	stfd 12,.LANCHOR0+2184@toc@l(10)
488,494c474,477
<       addis 7,2,.LC15@toc@ha
<       li 8,8
<       addi 9,10,2640
<       addi 7,7,.LC15@toc@l
<       sldi 10,8,56
<       lxv 0,0(7)
<       stxvl 0,9,10
---
> 	addis 9,2,.LC14@toc@ha
> 	lfd 0,.LC14@toc@l(9)
> 	addis 9,2,.LANCHOR0+2640@toc@ha
> 	stfd 0,.LANCHOR0+2640@toc@l(9)

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

Kewen Lin <linkw at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |linkw at gcc dot gnu.org
                 CC|                            |linkw at gcc dot gnu.org
   Last reconfirmed|                            |2020-09-17

--- Comment #1 from Kewen Lin <linkw at gcc dot gnu.org> ---
I'll take a look at this.

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[akrl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

akrl at gcc dot gnu.org changed:

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

--- Comment #2 from akrl at gcc dot gnu.org ---
Thanks Kewen, unfortunately I've no Power setup.  Sorry for the inconvenience.

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

--- Comment #3 from Kewen Lin <linkw at gcc dot gnu.org> ---
(In reply to akrl from comment #2)
> Thanks Kewen, unfortunately I've no Power setup.  Sorry for the
> inconvenience.

My pleasure! If you have interests to run on Power machines, you can apply and
use some Power8/Power9 machines in CFarm machine pool
https://cfarm.tetaneutral.net/machines/list/.

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

--- Comment #4 from Kewen Lin <linkw at gcc dot gnu.org> ---
> gcc.target/powerpc/p9-vec-length-full-6.c

This is a test case issue, 64bit/32bit pairs will use full vector instead of
partial vector as Andrea's improvement.

> gcc.target/powerpc/p9-vec-length-epil-7.c

It exposed one problem: when we call vect_need_peeling_or_partial_vectors_p in
function vect_analyze_loop_2, it's in analysis stage, if the loop is one
epilogue loop, the loop_vinfo hasn't been fixed up, like LOOP_VINFO_INT_NITERS,
the function can probably give the wrong answer.  For some 64bit type functions
of this failed case, it will return false for the epilogue loops but actually
the remaining iteration can't cover the full vector.

One simple fix is to exclude epilogue loop for this check.

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index ab627fbf029..7273e998a99 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -2278,7 +2278,8 @@ start_over:
     {
       /* Don't use partial vectors if we don't need to peel the loop.  */
       if (param_vect_partial_vector_usage == 0
-          || !vect_need_peeling_or_partial_vectors_p (loop_vinfo))
+          || (!LOOP_VINFO_EPILOGUE_P (loop_vinfo)
+              && !vect_need_peeling_or_partial_vectors_p (loop_vinfo)))
         LOOP_VINFO_USING_PARTIAL_VECTORS_P (loop_vinfo) = false;
       else if (vect_verify_full_masking (loop_vinfo)
                || vect_verify_loop_lens (loop_vinfo))

Testing is ongoing.

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Kewen Lin <linkw@gcc.gnu.org>:

https://gcc.gnu.org/g:5427bd4d57c0376e51fc7b256e76aa46c43aa8cf

commit r11-3422-g5427bd4d57c0376e51fc7b256e76aa46c43aa8cf
Author: Kewen Lin <linkw@linux.ibm.com>
Date:   Thu Sep 24 00:40:47 2020 -0500

    test: Adjust case p9-vec-length-full-6.c [PR97075]

    The commit r11-3230 brings a nice improvement to use full
    vectors instead of partial vectors when available.  This
    patch is to fix the test failures on p9-vec-length-full-6.c,
    where 64bit/32bit pairs are able to use full vector instead.

    Bootstrapped/regtested on powerpc64le-linux-gnu P9.

    gcc/testsuite/ChangeLog:

            PR tree-optimization/97075
            * gcc.target/powerpc/p9-vec-length-full-6.c: Adjust.

[Bug tree-optimization/97075] [11 regression] powerpc64 vector tests fails after r11-3230

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97075

Kewen Lin <linkw at gcc dot gnu.org> changed:

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

--- Comment #6 from Kewen Lin <linkw at gcc dot gnu.org> ---
Richard's rework r11-3393 has taken care of the failure on
gcc.target/powerpc/p9-vec-length-epil-7.c.  All failures should be gone on
latest trunk.