zhijian lin 36cb33bbca
support branch hint for AtomicExpandImpl::expandAtomicCmpXchg (#152366)
The patch add branch hint for AtomicExpandImpl::expandAtomicCmpXchg, For
example: in PowerPC, it support branch hint as

```
loop:
    lwarx r6,0,r3   #  load and reserve
    cmpw r4,r6      #1st 2 operands equal? bne- exit  #skip if not
    bne- exit       #skip if not
    stwcx. r5,0,r3  #store new value if still res’ved bne- loop #loop if lost reservation
    bne- loop #loop if lost reservation
exit:
    mr  r4,r6       #return value from storage
```

`-`  hints not taken,
`+` hints taken,
2025-09-02 09:33:28 -04:00
..
2025-05-22 15:42:22 +01:00