[Bug tree-optimization/109469] New: [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[Bug tree-optimization/109469] New: [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

            Bug ID: 109469
           Summary: [13 regression] ICE: internal compiler error:
                    verify_flow_info failed (error: returns_twice call is
                    not first in basic block 2)
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
  Target Milestone: ---

Hit this when building xdvik-22.87.06 with 13.0.1 20230409 w/ checking.

```
x86_64-pc-linux-gnu-gcc -DHAVE_CONFIG_H -I.  -I./gui -DPS_GS 
-I/usr/include/freetype2 -I/usr/include/harfbuzz -I/usr/include/glib-2.0
-I/usr/lib64/glib-2.0/include -I/usr/include   -Wimplicit -Wreturn-type -O2
-pipe -march=native -fdiagnostics-color=always -frecord-gcc-switches
-Wreturn-type      -ggdb3 -Werror=implicit-function-declaration
-Werror=implicit-int -Wformat -Waddress -Warray-bounds -Wfree-nonheap-object
-Wimplicit-function-declaration -Wimplicit-int -Wincompatible-pointer-types
-Wint-conversion -Wint-to-pointer-cast -Wmain -Wnonnull -Wodr -Wparentheses
-Wreturn-type -Wsizeof-pointer-memaccess -Wstrict-aliasing -Wstring-compare
-Wuninitialized -Wunused-value -Wvarargs -c -o util.o util.c
util.c: In function ‘fork_process’:
util.c:988:1: error: returns_twice call is not first in basic block 25
  988 | fork_process(const char *proc_name, Boolean redirect_stdout,
      | ^~~~~~~~~~~~
pid_96 = vfork ();
during GIMPLE pass: slp
util.c:988:1: internal compiler error: verify_flow_info failed
0x7aa668 verify_flow_info()
       
/usr/src/debug/sys-devel/gcc-13.0.1_pre20230409-r1/gcc-13-20230409/gcc/cfghooks.cc:285
0x151e50d execute_function_todo
       
/usr/src/debug/sys-devel/gcc-13.0.1_pre20230409-r1/gcc-13-20230409/gcc/passes.cc:2110
0x1485fd1 do_per_function
       
/usr/src/debug/sys-devel/gcc-13.0.1_pre20230409-r1/gcc-13-20230409/gcc/passes.cc:1694
0x1485fd1 execute_todo
       
/usr/src/debug/sys-devel/gcc-13.0.1_pre20230409-r1/gcc-13-20230409/gcc/passes.cc:2152
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://bugs.gentoo.org/> for instructions.
```

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
Created attachment 54826
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54826&action=edit
util.i.orig (unreduced)

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #2 from Sam James <sjames at gcc dot gnu.org> ---
Created attachment 54827
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54827&action=edit
util.i (reduced)

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #3 from Sam James <sjames at gcc dot gnu.org> ---
Created attachment 54828
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54828&action=edit
util2.i (reduced further, but check)

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #4 from Sam James <sjames at gcc dot gnu.org> ---
This might be a dupe of PR108783 or PR109410 but I had to try reduce it to be
relatively sure, so may as well file it here for completeness.

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #5 from Sam James <sjames at gcc dot gnu.org> ---
(In reply to Sam James from comment #4)
> This might be a dupe of PR108783 or PR109410 but I had to try reduce it to
> be relatively sure, so may as well file it here for completeness.

I thought it was interesting in this case that it happens even without a
definition of foo which was the main motivation for bothering here.

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

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

--- Comment #6 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
Not a dup. Why is SLP emitting a vector construction in BB 2 and not BB 4?
(-fno-tree-slp-vectorize disables it):

 void dummy_write_proc ()
 {
+  void (*<T24b>) () * vectp.4;
+  vector(2) long unsigned int * {ref-all} vectp_myproc.3;
+  long unsigned int _7;
+  long unsigned int _8;
+  vector(2) long unsigned int _9;
+
   <bb 2> [local count: 1073741824]:
+  _7 = VIEW_CONVERT_EXPR<long unsigned int>(dummy_write_proc);
+  _8 = VIEW_CONVERT_EXPR<long unsigned int>(dummy_write_proc);
+  _9 = {_8, _7};
   # DEBUG BEGIN_STMT
   foo ();
   goto <bb 4>; [99.96%]

   <bb 3> [local count: 429496]:
   .ABNORMAL_DISPATCHER (0);

   <bb 4> [local count: 1073312329]:
   # DEBUG BEGIN_STMT
-  myproc.write_proc = dummy_write_proc;
-  myproc.read_proc = dummy_write_proc;
+  MEM <vector(2) long unsigned int> [(void (*<T24b>) () *)&myproc] = _9;
   return;

 }

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2023-04-11
     Ever confirmed|0                           |1

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2) when building xdvik

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #8 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
*** Bug 109477 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2) when building xdvik

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #9 from CVS 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:2d7ad38707e1fd71193d440198cc0726092b9015

commit r13-7144-g2d7ad38707e1fd71193d440198cc0726092b9015
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Apr 11 16:06:12 2023 +0200

    tree-optimization/109469 - SLP with returns-twice region start

    The following avoids an SLP region starting with a returns-twice
    call where we cannot insert stmts at the head.

            PR tree-optimization/109469
            * tree-vect-slp.cc (vect_slp_function): Skip region starts with
            a returns-twice call.

            * gcc.dg/torture/pr109469.c: New testcase.

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2) when building xdvik

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED
           Keywords|                            |ice-checking,
                   |                            |ice-on-valid-code

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed (but latent).

[Bug tree-optimization/109469] [13 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2) when building xdvik

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|FIXED                       |---
   Target Milestone|13.0                        |12.3
             Status|RESOLVED                    |ASSIGNED
           Priority|P3                          |P2

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
On a 2nd thought I'm going to backport it for 12.3.

[Bug tree-optimization/109469] [12 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2) when building xdvik

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

--- Comment #12 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:9cc16b95d5d63b18cbc0aa780ffb6b460c791351

commit r12-9411-g9cc16b95d5d63b18cbc0aa780ffb6b460c791351
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Apr 11 16:06:12 2023 +0200

    tree-optimization/109469 - SLP with returns-twice region start

    The following avoids an SLP region starting with a returns-twice
    call where we cannot insert stmts at the head.

            PR tree-optimization/109469
            * tree-vect-slp.cc (vect_slp_function): Skip region starts with
            a returns-twice call.

            * gcc.dg/torture/pr109469.c: New testcase.

    (cherry picked from commit 2d7ad38707e1fd71193d440198cc0726092b9015)

[Bug tree-optimization/109469] [12 regression] ICE: internal compiler error: verify_flow_info failed (error: returns_twice call is not first in basic block 2) when building xdvik

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109469

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

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

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.