[Bug target/116445] New: gcc.target/arm/unsigned-extend-2.c on Cortex-M55 and misses possible Cortex-M optimization

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116445

            Bug ID: 116445
           Summary: gcc.target/arm/unsigned-extend-2.c on Cortex-M55 and
                    misses possible Cortex-M optimization
           Product: gcc
           Version: 13.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: azoff at gcc dot gnu.org
  Target Milestone: ---

Cortex-M55 does not generate optimal code for
gcc.target/arm/unsigned-extend-2.c.

For Cortex-M3, and other Thumb2 targets, the generated code is:
foo:
        movs    r3, #8
.L2:
        and     r0, r1, r0, lsr #1
        subs    r3, r3, #1
        ands    r3, r3, #255
        bne     .L2
        bx      lr


For Cortex-M55 it's instead:
foo:
        push    {lr}
        movs    r3, #8
        dls     lr, r3
.L2:
        and     r0, r1, r0, lsr #1
        subs    r3, r3, #1
        uxtb    r3, r3
        le      lr, .L2
        ldr     pc, [sp], #4