[Bug tree-optimization/111877] New: [14 Regression] ICE: verify_ssa failed: PHI node with wrong VUSE on edge from BB 25 with -O -fno-tree-sink -ftree-vectorize

[Bug tree-optimization/111877] New: [14 Regression] ICE: verify_ssa failed: PHI node with wrong VUSE on edge from BB 25 with -O -fno-tree-sink -ftree-vectorize

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111877

            Bug ID: 111877
           Summary: [14 Regression] ICE: verify_ssa failed: PHI node with
                    wrong VUSE on edge from BB 25 with -O -fno-tree-sink
                    -ftree-vectorize
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          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 56150
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56150&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O -fno-tree-sink -ftree-vectorize testcase.c
testcase.c: In function 'buffer_ctrl':
testcase.c:4:1: error: PHI node with wrong VUSE on edge from BB 25
    4 | buffer_ctrl (long ret, int i)
      | ^~~~~~~~~~~
.MEM_51 = PHI <.MEM_10(25), .MEM_10(22)>
expected .MEM_39
testcase.c:4:1: error: PHI node with wrong VUSE on edge from BB 22
.MEM_51 = PHI <.MEM_10(25), .MEM_10(22)>
expected .MEM_39
during GIMPLE pass: vect
testcase.c:4:1: internal compiler error: verify_ssa failed
0x172fccf verify_ssa(bool, bool)
        /repo/gcc-trunk/gcc/tree-ssa.cc:1203
0x1386415 execute_function_todo
        /repo/gcc-trunk/gcc/passes.cc:2095
0x138687e execute_todo
        /repo/gcc-trunk/gcc/passes.cc:2142
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ 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-r14-4710-20231018090306-g60c231cb658-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/14.0.0/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-r14-4710-20231018090306-g60c231cb658-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.0 20231018 (experimental) (GCC)

[Bug tree-optimization/111877] [14 Regression] ICE: verify_ssa failed: PHI node with wrong VUSE on edge from BB 25 with -O -fno-tree-sink -ftree-vectorize

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111877

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
                 CC|                            |tnfchris at gcc dot gnu.org

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
possibly fixed already

[Bug tree-optimization/111877] [14 Regression] ICE: verify_ssa failed: PHI node with wrong VUSE on edge from BB 25 with -O -fno-tree-sink -ftree-vectorize

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111877

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-10-19
           Assignee|unassigned at gcc dot gnu.org      |tnfchris at gcc dot gnu.org
           Priority|P3                          |P1

--- Comment #2 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> possibly fixed already

Sadly no, this is a third case where neither loop uses the value at all.

It's kept because the tree gets versioned and so it thinks the second loop
needs it.  I should probably always remove it if the first loop doesn't use it
and fix it up in the guard creation instead.

[Bug tree-optimization/111877] [14 Regression] ICE: verify_ssa failed: PHI node with wrong VUSE on edge from BB 25 with -O -fno-tree-sink -ftree-vectorize

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111877

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |DUPLICATE
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #3 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
merging the two

*** This bug has been marked as a duplicate of bug 111860 ***