[Bug rtl-optimization/61926] New: const-anchor optimisation is sensitive to ordering

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61926

            Bug ID: 61926
           Summary: const-anchor optimisation is sensitive to ordering
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rsandifo at gcc dot gnu.org
            Target: mips*-*-*

gcc.target/mips/const-anchor-1.c tests that cse uses constant anchors for:

  g (0x1233ffff, 0x12340001);

But this does not work for:

  g (0x12340001, 0x1233ffff);

since the constant that provides the 0x12340000 anchor then comes after
the constant that requires it.  Maybe this could fixed by doing the
anchor optimisation in gcse.c instead, although that probably isn't
trivial.

Related to PR33699.