[Bug c/100924] New: GCC 11.1.1 internal compiler error: segfault at VLA function definition

["christian.holme at med dot uni-goettingen.de" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100924

            Bug ID: 100924
           Summary: GCC 11.1.1 internal compiler error: segfault at VLA
                    function definition
           Product: gcc
           Version: 11.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: christian.holme at med dot uni-goettingen.de
  Target Milestone: ---

Created attachment 50949
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50949&action=edit
Failing source

Hey,

when compiling the attached vlatest_min.c, I encounter an internal compiler
error: segmentation fault with gcc 11.1.1. The precise version information
(collected with gcc -v) can be found in the attached compilation log.

With gcc master from 2021-06-02 it compiles without error.

Changing optimization level from -O3 to -O1 also removes the segfault, but -O2
still segfaults.

I have also attached the compiler output for both gcc 11 and 12 (master) and
the preprocessed files in both cases.

Since a fix for it exists on master, I am submitting this bug report in the
hopes that it will make it easier to fix in the next release of gcc 11.

Best regards