yaxunl marked 3 inline comments as done. yaxunl added a comment. In D71726#2047566 <https://reviews.llvm.org/D71726#2047566>, @ldionne wrote:
> In D71726#1791904 <https://reviews.llvm.org/D71726#1791904>, @jfb wrote: > > > This generally seems fine. Does it work on most backends? I want to make > > sure it doesn't fail in backends :) > > > > Also, @ldionne / @EricWF / @mclow.lists do you need this in libc++ for > > floating-point atomic support? > > > Yes, I guess we do in order to implement `fetch_add` & friends on floating > point types (https://wg21.link/P0020R6). > > The builtins would need to work on `float`, `double` and `long double`. The > code seems to suggest it does, however the tests only check for `float`. Does > this support `__atomic_fetch_{add,sub}` on `double` and `long double`? It depends on target. For x86_64, `__atomic_fetch_{add,sub}` on `double` and `long double` are translated to `__atomic_fetch_sub_8` and `__atomic_fetch_sub_16`. For amdgcn, `__atomic_fetch_{add,sub}` on `double` is translated to fp atomic insts. `long double` is the same as `double` on amdgcn. ================ Comment at: clang/test/CodeGen/atomic-ops.c:296 + // CHECK: fsub + return __atomic_sub_fetch(p, 1.0, memory_order_relaxed); +} ---------------- ldionne wrote: > Sorry if that's a dumb question, but I'm a bit confused: `p` is a `float*`, > but then we add a double `1.0` to it. Is that intended, or should that be > `double *p` instead (or `1.0f`)? In this case, the value type is converted to the pointee type of the pointer operand. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D71726/new/ https://reviews.llvm.org/D71726 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
