[Bug tree-optimization/121298] New: [16 Regression] Missed bswap and rotate detection from r16-2601-ge8a51144c02e1c

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121298

            Bug ID: 121298
           Summary: [16 Regression] Missed bswap and rotate detection from
                    r16-2601-ge8a51144c02e1c
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

FAIL: gcc.target/i386/pr115102.c scan-assembler bswaphisi2_lowpart
FAIL: gcc.target/i386/xchg-4.c scan-assembler rolw
FAIL: gcc.target/i386/xchg-4.c scan-assembler-not mov

is caused by the rev. the rotate detection in tree-ssa-forwprop.cc and
the bswap detection in gimple-ssa-store-merging.cc do not cope with
the changed association of three-element bitwise IORs.