[Bug target/97042] New: powerpc64 UINT_MAX constant

[amodra at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97042

            Bug ID: 97042
           Summary: powerpc64 UINT_MAX constant
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: amodra at gmail dot com
  Target Milestone: ---

/* -O2 -S */
long foo (long x) { return ~0u - x; }

for gcc-8 to current master
        lis 9,0xffff
        ori 9,9,0xffff
        rldicl 9,9,0,32
        subf 3,3,9
        blr

a regression from gcc-7
        li 9,-1
        rldicl 9,9,0,32
        subf 3,3,9
        blr

Both sequences give the same result, this is just a code quality regression.

I haven't properly debugged this but I suspect commit 5d3ae76af13