[Bug c++/105786] New: ICE in compute_distributive_range, at tree-data-ref.cc:593

[Bug c++/105786] New: ICE in compute_distributive_range, at tree-data-ref.cc:593

[gcc at olupton dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

            Bug ID: 105786
           Summary: ICE in compute_distributive_range, at
                    tree-data-ref.cc:593
           Product: gcc
           Version: 12.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc at olupton dot com
  Target Milestone: ---

The following example:

```
void sink(const char*);
static const char *a;
int main() {
  const char *b = a;
  for (int i = 0; i < 2; ++i)
    while (*b++)
      ;
  sink(b);
  return 0;
}
```

produces an ICE at -O2 and above with 12.1:

```
during GIMPLE pass: pcom
<source>: In function 'int main()':
<source>:3:5: internal compiler error: in compute_distributive_range, at
tree-data-ref.cc:593
    3 | int main() {
      |     ^~~~
```

this is reproducible on Compiler Explorer (https://godbolt.org/z/z1zrqrrEs) and
also using 12.1.1 installed via `dnf` in a `fedora:latest` Docker container.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102853 reports a similar error
message, but it says the issue is resolved so opening this new issue seems
justified.

Note that adding
```
void set_a(const char* x) {
    a = x;
}
```
so that `a` can be non-null avoids the ICE.

[Bug tree-optimization/105786] ICE in compute_distributive_range, at tree-data-ref.cc:593

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

Alex Coplan <acoplan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-05-31
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
      Known to fail|                            |13.0
                 CC|                            |acoplan at gcc dot gnu.org

--- Comment #1 from Alex Coplan <acoplan at gcc dot gnu.org> ---
Confirmed on trunk (on aarch64). I see:

t.c: In function ‘main’:
t.c:3:5: error: invalid (pointer) operands ‘plus_expr’
    3 | int main() {
      |     ^~~~
_5 = _23 + 1B;
during GIMPLE pass: ldist
t.c:3:5: internal compiler error: verify_gimple failed
0xeef45f verify_gimple_in_cfg(function*, bool)
        /home/alecop01/toolchain/src/gcc/gcc/tree-cfg.cc:5551
0xd79b3b execute_function_todo
        /home/alecop01/toolchain/src/gcc/gcc/passes.cc:2085
0xd7a6ab execute_todo
        /home/alecop01/toolchain/src/gcc/gcc/passes.cc:2139
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.

[Bug tree-optimization/105786] ICE in compute_distributive_range, at tree-data-ref.cc:593 since r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

Alex Coplan <acoplan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE in                      |ICE in
                   |compute_distributive_range, |compute_distributive_range,
                   |at tree-data-ref.cc:593     |at tree-data-ref.cc:593
                   |                            |since
                   |                            |r12-4283-g6f966f06146be7689
                   |                            |af471d152e18ff50c609d99

--- Comment #2 from Alex Coplan <acoplan at gcc dot gnu.org> ---
The above ICE started with r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[Bug tree-optimization/105786] [12/13 Regression] ICE in compute_distributive_range, at tree-data-ref.cc:593 since r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[acoplan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

Alex Coplan <acoplan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |stefansf at linux dot ibm.com

--- Comment #3 from Alex Coplan <acoplan at gcc dot gnu.org> ---
And with -fno-checking I indeed see the original ICE in
compute_distributive_range instead.

[Bug tree-optimization/105786] [12/13 Regression] ICE in compute_distributive_range, at tree-data-ref.cc:593 since r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
           Priority|P3                          |P2
   Target Milestone|---                         |12.2

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Testing patch.

[Bug tree-optimization/105786] [12/13 Regression] ICE in compute_distributive_range, at tree-data-ref.cc:593 since r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

--- Comment #5 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:57a8fb92ac4161ebbf9381b009e8c5af843e3e5f

commit r13-913-g57a8fb92ac4161ebbf9381b009e8c5af843e3e5f
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jun 1 14:13:01 2022 +0200

    tree-optimization/105786 - avoid strlen replacement for pointers

    This avoids matching strlen to a pointer result, avoiding ICEing
    because of an integer adjustment using PLUS_EXPR on pointers.

    2022-06-01  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/105786
            * tree-loop-distribution.cc
            (loop_distribution::transform_reduction_loop): Only do strlen
            replacement for integer type reductions.

            * gcc.dg/torture/pr105786.c: New testcase.

[Bug tree-optimization/105786] [12 Regression] ICE in compute_distributive_range, at tree-data-ref.cc:593 since r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

--- Comment #6 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:9f1e32c69d3f0cc04665587c18937a773616c6bd

commit r12-8453-g9f1e32c69d3f0cc04665587c18937a773616c6bd
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jun 1 14:13:01 2022 +0200

    tree-optimization/105786 - avoid strlen replacement for pointers

    This avoids matching strlen to a pointer result, avoiding ICEing
    because of an integer adjustment using PLUS_EXPR on pointers.

    2022-06-01  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/105786
            * tree-loop-distribution.cc
            (loop_distribution::transform_reduction_loop): Only do strlen
            replacement for integer type reductions.

            * gcc.dg/torture/pr105786.c: New testcase.

    (cherry picked from commit 57a8fb92ac4161ebbf9381b009e8c5af843e3e5f)

[Bug tree-optimization/105786] [12 Regression] ICE in compute_distributive_range, at tree-data-ref.cc:593 since r12-4283-g6f966f06146be7689af471d152e18ff50c609d99

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105786

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

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

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.