[llvm-bugs] [Bug 60941] [Missing optimization] Atomic add or subtract a pointer

[LLVM Bugs via llvm-bugs]

Issue	60941
Summary	[Missing optimization] Atomic add or subtract a pointer
Labels	new issue
Assignees
Reporter	youngbe

    src:
```c
#include <stdatomic.h>
#include <stdint.h>
_Atomic(uintptr_t) y;
_Atomic(uint8_t *) x;
void ppp()
{
    ++x;
 ++y;
}
```

gcc-12 -Ofast:
```
ppp:
    lock addq   $1, x(%rip)
    lock addq   $1, y(%rip)
    ret
```

clang 15.0.6 -Ofast:
```
ppp:                                    # @ppp
.Lppp$local:
    movq    .Lx$local(%rip), %rax
    .p2align 4, 0x90
.LBB0_1:                                # =>This Inner Loop Header: Depth=1
    leaq    1(%rax), %rcx
    lock        cmpxchgq %rcx, .Lx$local(%rip)
    jne .LBB0_1
    lock        incq .Ly$local(%rip)
    retq
```

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