[Bug tree-optimization/88973] New: New -Wrestrict warning since r268048

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88973

            Bug ID: 88973
           Summary: New -Wrestrict warning since r268048
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: msebor at gcc dot gnu.org
  Target Milestone: ---

Created attachment 45492
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45492&action=edit
test-case

The test-case comes from autogen package:

$ gcc autogen.i -c -O2 -Werror=restrict
In function ‘strcpy’,
    inlined from ‘canonicalize_pathname’ at autogen.i:10536:17,
    inlined from ‘option_pathfind.constprop’ at autogen.i:10420:32:
autogen.i:4050:10: error: ‘__builtin_strcpy’ accessing 1 byte at offsets [0,
9223372036854775807] and [0, 9223372036854775807] may overlap 1 byte at offset
0 [-Werror=restrict]
 4050 |   return __builtin___strcpy_chk (__dest, __src, __builtin_object_size
(__dest, 2 > 1));
      |         
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

Martin can you please verify that the warning is correct?