[Bug target/115652] New: [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[Bug target/115652] New: [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

            Bug ID: 115652
           Summary: [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c
                    (internal compiler error: verify_ssa failed)
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: ice-checking, ice-on-valid-code, testsuite-fail
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: ams at gcc dot gnu.org, rguenth at gcc dot gnu.org
  Target Milestone: ---
            Target: GCN

As of commit r15-1056-g4653b682ef161c3c2fc7bf8462b8f9206a1349e6 "Allow
single-lane SLP in-order reductions" we've got a '-fchecking' ICE regression
for GCN target (tested '-march=gfx908'):

    {+FAIL: gcc.dg/vect/pr70138-1.c (internal compiler error: verify_ssa
failed)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/pr70138-1.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/pr70138-1.c [-execution
test-]{+compilation failed to produce executable+}

    [...]/source-gcc/gcc/testsuite/gcc.dg/vect/pr70138-1.c: In function 'foo':
    [...]/source-gcc/gcc/testsuite/gcc.dg/vect/pr70138-1.c:6:1: error:
definition in block 3 follows the use
    for SSA_NAME: stmp_c_17.9_153 in statement:
    c_17 = stmp_c_17.9_153 + stmp_c_17.9_154;
    during GIMPLE pass: vect
    dump file: ./pr70138-1.c.180t.vect
    [...]/source-gcc/gcc/testsuite/gcc.dg/vect/pr70138-1.c:6:1: internal
compiler error: verify_ssa failed
    0x142272d verify_ssa(bool, bool)
            [...]/source-gcc/gcc/tree-ssa.cc:1203

    {+FAIL: gcc.dg/vect/pr70138-2.c (internal compiler error: verify_ssa
failed)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/pr70138-2.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/pr70138-2.c [-execution
test-]{+compilation failed to produce executable+}

    [...]/source-gcc/gcc/testsuite/gcc.dg/vect/pr70138-2.c: In function 'foo':
    [...]/source-gcc/gcc/testsuite/gcc.dg/vect/pr70138-2.c:6:1: error:
definition in block 3 follows the use
    for SSA_NAME: stmp_c_15.9_152 in statement:
    c_15 = stmp_c_15.9_152 + stmp_c_15.9_153;
    during GIMPLE pass: vect
    dump file: ./pr70138-2.c.180t.vect
    [...]/source-gcc/gcc/testsuite/gcc.dg/vect/pr70138-2.c:6:1: internal
compiler error: verify_ssa failed
    0x142272d verify_ssa(bool, bool)
            [...]/source-gcc/gcc/tree-ssa.cc:1203

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|target                      |tree-optimization
   Target Milestone|---                         |15.0
                 CC|                            |pinskia at gcc dot gnu.org

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
   Last reconfirmed|                            |2024-06-26
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:f80db5495d5f8455b3003951727eb6c8dc67d81d

commit r15-1653-gf80db5495d5f8455b3003951727eb6c8dc67d81d
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jun 26 09:25:27 2024 +0200

    tree-optimization/115652 - adjust insertion gsi for SLP

    The following adjusts how SLP computes the insertion location.  In
    particular it advanced the insert iterator of the found last_stmt.
    The vectorizer will later insert stmts _before_ it.  But we also
    have the constraint that possibly masked ops may not be scheduled
    outside of the loop and as we do not model the loop mask in the
    SLP graph we have to adjust for that.  The following moves this
    to after the advance since it isn't compatible with that as the
    current GIMPLE_COND exception shows.  The PR is about in-order
    reduction vectorization which also isn't happy when that's the
    very first stmt.

            PR tree-optimization/115652
            * tree-vect-slp.cc (vect_schedule_slp_node): Advance the
            iterator based on last_stmt only for vector defs.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

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

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

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
This should be fixed.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

Jeffrey A. Law <law at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at gcc dot gnu.org
         Resolution|FIXED                       |---
             Status|RESOLVED                    |REOPENED

--- Comment #4 from Jeffrey A. Law <law at gcc dot gnu.org> ---
That patch seems to be causing ssa verification failures (should be visible
with riscv64-elf cross):

make check-gcc RUNTESTFLAGS=rvv.exp=vsetvl_bug-2.c

Running
/home/jlaw/jenkins/workspace/riscv64-elf/gcc/gcc/testsuite/gcc.target/riscv/rvv/rvv.exp
...
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O0  (internal compiler
error: verify_ssa failed)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O0  (test for excess
errors)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O1  (internal compiler
error: verify_ssa failed)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O1  (test for excess
errors)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O2  (internal compiler
error: verify_ssa failed)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O2  (test for excess
errors)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions  (internal compiler
error: verify_ssa failed)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions  (test for excess
errors)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -g  (internal compiler
error: verify_ssa failed)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -g  (test for excess
errors)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -Os  (internal compiler
error: verify_ssa failed)
FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -Os  (test for excess
errors)

There's a handful of other failures since yesterday, but I suspect they're all
the same root cause.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #4)
> That patch seems to be causing ssa verification failures (should be visible
> with riscv64-elf cross):
> 
> make check-gcc RUNTESTFLAGS=rvv.exp=vsetvl_bug-2.c
> 
> Running
> /home/jlaw/jenkins/workspace/riscv64-elf/gcc/gcc/testsuite/gcc.target/riscv/
> rvv/rvv.exp ...
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O0  (internal compiler
> error: verify_ssa failed)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O0  (test for excess
> errors)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O1  (internal compiler
> error: verify_ssa failed)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O1  (test for excess
> errors)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O2  (internal compiler
> error: verify_ssa failed)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O2  (test for excess
> errors)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -fomit-frame-pointer
> -funroll-loops -fpeel-loops -ftracer -finline-functions  (internal compiler
> error: verify_ssa failed)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -fomit-frame-pointer
> -funroll-loops -fpeel-loops -ftracer -finline-functions  (test for excess
> errors)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -g  (internal
> compiler error: verify_ssa failed)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -O3 -g  (test for excess
> errors)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -Os  (internal compiler
> error: verify_ssa failed)
> FAIL: gcc.target/riscv/rvv/vsetvl/vsetvl_bug-2.c   -Os  (test for excess
> errors)
> 
> There's a handful of other failures since yesterday, but I suspect they're
> all the same root cause.

I can reproduce the above, we get

  vect__85.21_1 = .COND_LEN_XOR ({ -1, ... }, vect_l_437__lsm.13_110.20_2,
vect__87.19_22, vect_l_437__lsm.13_110.20_2, loop_len_54, 0);
  vect__87.19_22 = (vector([32,32]) int) vect__90.18_9;

I'm testing a fix:

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 896ea6dc14c..ce214dd652e 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -9752,7 +9752,8 @@ vect_schedule_slp_node (vec_info *vinfo,
              {
                gimple_stmt_iterator si2
                  = gsi_after_labels (LOOP_VINFO_LOOP (loop_vinfo)->header);
-               if (vect_stmt_dominates_stmt_p (last_stmt, *si2))
+               if (last_stmt != *si2
+                   && vect_stmt_dominates_stmt_p (last_stmt, *si2))
                  si = si2;
              }
        }

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:c7cb0dd94589ab501bca27f93641b4074e5a2e99

commit r15-1670-gc7cb0dd94589ab501bca27f93641b4074e5a2e99
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jun 26 19:23:26 2024 +0200

    tree-optimization/115652 - amend last fix

    The previous fix breaks in the degenerate case when the discovered
    last_stmt is equal to the first stmt in the block since then we
    undo a required stmt advancement.

            PR tree-optimization/115652
            * tree-vect-slp.cc (vect_schedule_slp_node): Only insert
            at the start of the block if that strictly dominates
            the discovered dependent stmt.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

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

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

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Should be fixed again.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

Thomas Schwinge <tschwinge at gcc dot gnu.org> changed:

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

--- Comment #8 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
Richard, thanks for looking into this!

I confirm 'gcc.dg/vect/pr70138-1.c', 'gcc.dg/vect/pr70138-2.c' restored to
PASSing, but as of commit r15-1653-gf80db5495d5f8455b3003951727eb6c8dc67d81d
"tree-optimization/115652 - adjust insertion gsi for SLP", we've now got a
bunch of other ICEs for GCN target (tested '-march=gfx908').  (These are not
addressed by follow-up commit
r15-1670-gc7cb0dd94589ab501bca27f93641b4074e5a2e99 "tree-optimization/115652 -
amend last fix".)

    PASS: gcc.dg/torture/pr111614.c   -O0  (test for excess errors)
    PASS: gcc.dg/torture/pr111614.c   -O1  (test for excess errors)
    {+FAIL: gcc.dg/torture/pr111614.c   -O2  (internal compiler error:
Segmentation fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/torture/pr111614.c   -O2  (test for excess
errors)
    PASS: gcc.dg/torture/pr111614.c   -O3 -fomit-frame-pointer -funroll-loops
-fpeel-loops -ftracer -finline-functions  (test for excess errors)
    PASS: gcc.dg/torture/pr111614.c   -O3 -g  (test for excess errors)
    PASS: gcc.dg/torture/pr111614.c   -Os  (test for excess errors)

    during GIMPLE pass: vect
    [...]/gcc/testsuite/gcc.dg/torture/pr111614.c: In function 'main':
    [...]/gcc/testsuite/gcc.dg/torture/pr111614.c:19:5: internal compiler
error: Segmentation fault
    0x20dcac2 internal_error(char const*, ...)
            [...]/gcc/diagnostic-global-context.cc:491
    0x11af353 crash_signal
            [...]/gcc/toplev.cc:319
    0x7f8fc0faf51f ???
            ./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
    0x14e6513 gimple_bb(gimple const*)
            [...]/gcc/gimple.h:1909
    0x14e6513 vect_stmt_dominates_stmt_p(gimple*, gimple*)
            [...]/gcc/tree-vectorizer.cc:775
    0x14bf1e5 vect_schedule_slp_node
            [...]/gcc/tree-vect-slp.cc:9754
    0x14d609f vect_schedule_slp_node
            [...]/gcc/tree-vect-slp.cc:9583
    0x14d609f vect_schedule_scc
            [...]/gcc/tree-vect-slp.cc:10025
    0x14d6038 vect_schedule_scc
            [...]/gcc/tree-vect-slp.cc:10006
    0x14d6038 vect_schedule_scc
            [...]/gcc/tree-vect-slp.cc:10006
    0x14d6038 vect_schedule_scc
            [...]/gcc/tree-vect-slp.cc:10006
    0x14d6038 vect_schedule_scc
            [...]/gcc/tree-vect-slp.cc:10006
    0x14d6797 vect_schedule_slp(vec_info*, vec<_slp_instance*, va_heap, vl_ptr>
const&)
            [...]/gcc/tree-vect-slp.cc:10170
    0x14a2a41 vect_transform_loop(_loop_vec_info*, gimple*)
            [...]/gcc/tree-vect-loop.cc:12114
    0x14e7614 vect_transform_loops
            [...]/gcc/tree-vectorizer.cc:1007
    0x14e7ce3 try_vectorize_loop_1
            [...]/gcc/tree-vectorizer.cc:1153
    0x14e7ce3 try_vectorize_loop
            [...]/gcc/tree-vectorizer.cc:1183
    0x14e836c execute
            [...]/gcc/tree-vectorizer.cc:1299

Similarly:

    {+FAIL: gcc.dg/vect/ggc-pr37574.c (internal compiler error: Segmentation
fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/ggc-pr37574.c (test for excess errors)

    {+FAIL: gcc.dg/vect/no-scevccp-outer-13.c (internal compiler error:
Segmentation fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/no-scevccp-outer-13.c (test for excess
errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/no-scevccp-outer-13.c [-execution
test-]{+compilation failed to produce executable+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/no-scevccp-outer-13.c scan-tree-dump-times
vect "OUTER LOOP VECTORIZED." 1

    {+FAIL: gcc.dg/vect/no-scevccp-outer-18.c (internal compiler error:
Segmentation fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/no-scevccp-outer-18.c (test for excess
errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/no-scevccp-outer-18.c [-execution
test-]{+compilation failed to produce executable+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/no-scevccp-outer-18.c scan-tree-dump-times
vect "OUTER LOOP VECTORIZED." 1

    {+FAIL: gcc.dg/vect/no-scevccp-outer-7.c (internal compiler error:
Segmentation fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/no-scevccp-outer-7.c (test for excess
errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/no-scevccp-outer-7.c [-execution
test-]{+compilation failed to produce executable+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/no-scevccp-outer-7.c scan-tree-dump-times
vect "OUTER LOOP VECTORIZED." 1
    PASS: gcc.dg/vect/no-scevccp-outer-7.c scan-tree-dump-times vect
"vect_recog_widen_mult_pattern: detected(?:(?!Analysis failed).)*Analysis
succeeded" 1

    {+FAIL: gcc.dg/vect/vect-outer-4i.c (internal compiler error: Segmentation
fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/vect-outer-4i.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/vect-outer-4i.c [-execution
test-]{+compilation failed to produce executable+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/vect-outer-4i.c scan-tree-dump-times vect
"OUTER LOOP VECTORIZED" 1

    {+FAIL: gcc.dg/vect/vect-outer-4m.c (internal compiler error: Segmentation
fault)+}
    [-PASS:-]{+FAIL:+} gcc.dg/vect/vect-outer-4m.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/vect/vect-outer-4m.c [-execution
test-]{+compilation failed to produce executable+}
    XFAIL: gcc.dg/vect/vect-outer-4m.c scan-tree-dump-times vect "OUTER LOOP
VECTORIZED" 1

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:ff6e8b7f09712bd7ddfcd2830b286421f23abef9

commit r15-1709-gff6e8b7f09712bd7ddfcd2830b286421f23abef9
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Jun 28 13:29:21 2024 +0200

    tree-optimization/115652 - more fixing of the fix

    The following addresses the corner case of an outer loop with an empty
    header where we end up asking for the BB of a NULL stmt by
    special-casing this case.

            PR tree-optimization/115652
            * tree-vect-slp.cc (vect_schedule_slp_node): Handle the case
            where the outer loop header block is empty.

[Bug tree-optimization/115652] [15 Regression] GCN: FAIL: gcc.dg/vect/pr70138-{1,2}.c (internal compiler error: verify_ssa failed)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115652

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

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

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Next try ;)