[PATCH] D71726: Let clang atomic builtins fetch add/sub support floating point types

[John McCall via Phabricator via cfe-commits]

rjmccall added inline comments.


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Comment at: clang/lib/Sema/SemaChecking.cpp:5011
+        !ValType->isFloatingType()) {
+      Diag(ExprRange.getBegin(), diag::err_atomic_op_needs_atomic_int_ptr_or_fp)
           << IsC11 << Ptr->getType() << Ptr->getSourceRange();
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yaxunl wrote:
> rjmccall wrote:
> > Does LLVM support atomics on all floating-point types?
> LLVM IR parser requires atomicrmw value operand must have size of power of 2, therefore LLVM does not support atomicrmw on x86_fp80 which has size of 80 bytes. LLVM supports atomicrmw on all other floating-point types (bfloat, half, float, double, fp128, ppc_fp128).
Okay.  So this needs to check the underlying FP semantics and disallow atomics on unsupported types.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71726/new/

https://reviews.llvm.org/D71726