[llvm-bugs] [Bug 34821] New: __sync_and_fetch_min/max/umin/umax builtins don't support different size overloads

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=34821

            Bug ID: 34821
           Summary: __sync_and_fetch_min/max/umin/umax builtins don't
                    support different size overloads
           Product: clang
           Version: trunk
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Frontend
          Assignee: unassignedclangbugs at nondot.org
          Reporter: gberry at codeaurora.org
                CC: llvm-bugs at lists.llvm.org

llvm/docs/Atomics.rst lists these builtins as being supported for sizes of 1,
2, 4, 8, or 16, but that doesn't seem to be the case.
For example, on aarch64 where long is 8 bytes:

long atomic64(void) {
  long old;
  long val = 1;
  unsigned long uval = 1;

  old = __sync_fetch_and_min(&val, 3);
  old = __sync_fetch_and_max(&val, 4);
  old = __sync_fetch_and_umin(&uval, 5);
  old = __sync_fetch_and_umax(&uval, 6);

  old = __sync_fetch_and_min_8(&val, 3);
  old = __sync_fetch_and_max_8(&val, 4);
  old = __sync_fetch_and_umin_8(&uval, 5);
  old = __sync_fetch_and_umax_8(&uval, 6);

  return old;
}

generates the following warnings and generates a 32-bit atomic op in the first
case and a function call to an unknown function in the second:

atomic.c:19:30: warning: incompatible pointer types passing 'long *' to
parameter of type 'volatile int *'
      [-Wincompatible-pointer-types]
  old = __sync_fetch_and_min(&val, 3);
                             ^~~~
atomic.c:20:30: warning: incompatible pointer types passing 'long *' to
parameter of type 'volatile int *'
      [-Wincompatible-pointer-types]
  old = __sync_fetch_and_max(&val, 4);
                             ^~~~
atomic.c:21:31: warning: incompatible pointer types passing 'unsigned long *'
to parameter of type
      'volatile unsigned int *' [-Wincompatible-pointer-types]
  old = __sync_fetch_and_umin(&uval, 5);
                              ^~~~~
atomic.c:22:31: warning: incompatible pointer types passing 'unsigned long *'
to parameter of type
      'volatile unsigned int *' [-Wincompatible-pointer-types]
  old = __sync_fetch_and_umax(&uval, 6);
                              ^~~~~
atomic.c:24:9: warning: implicit declaration of function
'__sync_fetch_and_min_8' is invalid in C99
      [-Wimplicit-function-declaration]
  old = __sync_fetch_and_min_8(&val, 3);
        ^
atomic.c:25:9: warning: implicit declaration of function
'__sync_fetch_and_max_8' is invalid in C99
      [-Wimplicit-function-declaration]
  old = __sync_fetch_and_max_8(&val, 4);
        ^
atomic.c:26:9: warning: implicit declaration of function
'__sync_fetch_and_umin_8' is invalid in C99
      [-Wimplicit-function-declaration]
  old = __sync_fetch_and_umin_8(&uval, 5);
        ^
atomic.c:27:9: warning: implicit declaration of function
'__sync_fetch_and_umax_8' is invalid in C99
      [-Wimplicit-function-declaration]
  old = __sync_fetch_and_umax_8(&uval, 6);

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