[Bug c/123604] New: Regression: GCC 15 creates 50 % longer loop than GCC 14

[kuratius at googlemail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123604

            Bug ID: 123604
           Summary: Regression: GCC 15 creates 50 % longer loop than GCC
                    14
           Product: gcc
           Version: 15.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kuratius at googlemail dot com
  Target Milestone: ---

There's a regression in gcc 15:
gcc 14 compiles the loop to 4 instructions per iteration
https://godbolt.org/z/GrdMMP1fT

gcc 15 compiles it to 6 instructions per iteration:
https://godbolt.org/z/rEaW4dP68