[AArch64] Combine `and` and `lsl` into `ubfiz`

[Kmeakin]

https://godbolt.org/z/jxbMMs3dP

uint64_t u8(uint8_t x) { return x << 1; }
uint64_t u16(uint16_t x) { return x << 1; }

clang output:

u8:
        and     x8, x0, #0xff
        lsl     x0, x8, #1
        ret

u16:
        and     x8, x0, #0xffff
        lsl     x0, x8, #1
        ret

GCC output:

u8:
        ubfiz   x0, x0, 1, 8
        ret
u16:
        ubfiz   x0, x0, 1, 16
        ret

[llvmbot]

@llvm/issue-subscribers-backend-aarch64

Author: Karl Meakin (Kmeakin)

https://godbolt.org/z/jxbMMs3dP

uint64_t u8(uint8_t x) { return x << 1; }
uint64_t u16(uint16_t x) { return x << 1; }

clang output:

u8:
        and     x8, x0, #<!-- -->0xff
        lsl     x0, x8, #<!-- -->1
        ret

u16:
        and     x8, x0, #<!-- -->0xffff
        lsl     x0, x8, #<!-- -->1
        ret

GCC output:

u8:
        ubfiz   x0, x0, 1, 8
        ret
u16:
        ubfiz   x0, x0, 1, 16
        ret

[c-rhodes]

thanks @Kmeakin, I'll pick this one up 👍

[c-rhodes]

had to revert due to compilation hang, reopening.

[c-rhodes]

new PR with fix for hang #124576