[Bug tree-optimization/108356] [13 Regression] Dead Code Elimination Regression at -O2 since r13-434-g6b156044c12bc4

[amacleod at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108356

--- Comment #5 from Andrew Macleod <amacleod at redhat dot com> ---
The full comment is the test case is:

/* Verify offsets in an anti-range.  */
<...>

 /* The initial source range is valid but the final range after the access
     has complete cannot be.  The value mentioned in the warning is the final
     offset, i.e., 7 + 3.  Including the whole final range because would be
     confusing (the upper bound would either be negative or a very large
     positive number) so only the lower bound is included.  */
  T (char, 9, a, a + SAR ( 0,  6), 3);   /* { dg-warning "forming offset 9 is
out of the bounds \\\[0, 9] of object " "memcpy" } */

I'm not sure what it means exactly, but I presume -1 is a bad thing. I find it
marginally disturbing that this is happening in a function that is focused on
"verifying offsets in an anti-range"  as we move away from anti-ranges. 

That one of 7 warnings affected in this function.