[Bug target/104307] New: [11/12 Regression] '-fcompare-debug' failure (length) w/ -mavx512f -O2

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104307

            Bug ID: 104307
           Summary: [11/12 Regression] '-fcompare-debug' failure (length)
                    w/ -mavx512f -O2
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: compare-debug-failure
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: x86_64-unknown-linux-gnu

Created attachment 52319
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52319&action=edit
gkd diff

gcc 12.0.1 20220123 snapshot (g:2da90ad39bf8fa9ee287e040d1f4411cb7a2e7ed) fails
-fcompare-debug check when compiling gcc/testsuite/gcc.target/i386/pr78669.c w/
-Os -funroll-loops:

% x86_64-unknown-linux-gnu-gcc-12.0.1 -mavx512f -O2 -fcompare-debug
-gno-statement-frontiers -c gcc/testsuite/gcc.target/i386/pr78669.c
x86_64-unknown-linux-gnu-gcc-12.0.1: error:
gcc/testsuite/gcc.target/i386/pr78669.c: '-fcompare-debug' failure (length)

gkd diff attached.

-fcompare-debug check also fails w/o -mavx512f, though the diff is different.

If I get the dumps right, this issue is not related to PR104054, as things
already start looking interesting since veclower21 tree dump.