[Bug tree-optimization/100873] New: [12 Regression] gcc.target/aarch64/subs_compare_2.c fails since r12-1152-g9f55df63

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100873

            Bug ID: 100873
           Summary: [12 Regression] gcc.target/aarch64/subs_compare_2.c
                    fails since r12-1152-g9f55df63
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: acoplan at gcc dot gnu.org
  Target Milestone: ---

For the test gcc.target/aarch64/subs_compare_2.c, we used to generate:

foo:
        subs    w0, w0, 4
        csel    w0, w0, wzr, lt
        ret

but since r12-1152-g9f55df63154a39d67ef5b24def7044bf87300831 we generate:

foo:
        mov     w1, 4
        cmp     w0, w1
        csel    w0, w0, w1, le
        sub     w0, w0, #4
        ret