[PATCH] D24609: [ARM] Add missing Interlocked intrinsics

[Martin Storsjö via cfe-commits]

mstorsjo added inline comments.

================
Comment at: lib/Headers/intrin.h:504
@@ +503,3 @@
+_interlockedbittestandset_acq(long volatile *_BitBase, long _BitPos) {
+  long _PrevVal = __atomic_fetch_or(_BitBase, 1l << _BitPos, __ATOMIC_ACQUIRE);
+  return (_PrevVal >> _BitPos) & 1;
----------------
compnerd wrote:
> Perhaps we should add static asserts that _BitPos is within limits for the signed shift.
Sure, although I guess that also goes for the existing inline functions as well?

Which kind of assert would be suitable for that here? As far as I see, static_assert is C++ only, while this header also can be used from C.

If I try to add _Static_assert, which is usable in C, I get the following error when compiling:

intrin.h:499:18: error: 
      static_assert expression is not an integral constant expression
  _Static_assert(_BitPos < 32, "_BitPos out of range");

This even when I don't actually use the inline function anywhere, just including intrin.h.

================
Comment at: lib/Headers/intrin.h:517
@@ -501,1 +516,3 @@
+}
+#endif
 #ifdef __x86_64__
----------------
compnerd wrote:
> Are the names supposed to be all lower case?
Yes, these ones (for some reason) are all lower case:
https://msdn.microsoft.com/en-us/library/646k06sz.aspx


https://reviews.llvm.org/D24609