Sema: demote invalid atomic ordering message to warning.

Someone could write:
  if (0) {
    __c11_atomic_load(ptr, memory_order_release);
  }

or the equivalent, which is perfectly valid, so we shouldn't outright reject
invalid orderings on purely static grounds.

rdar://problem/16242991

llvm-svn: 203564

3 files changed, 23 insertions, 22 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 8ec965bd6ca..c9bdcf12cb6 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5689,8 +5689,9 @@ def err_atomic_op_needs_atomic_int_or_ptr : Error<
 def err_atomic_op_bitwise_needs_atomic_int : Error<
   "address argument to bitwise atomic operation must be a pointer to "
   "%select{|atomic }0integer (%1 invalid)">;
-def err_atomic_op_has_invalid_memory_order : Error<
-  "memory order argument to atomic operation is invalid">;
+def warn_atomic_op_has_invalid_memory_order : Warning<
+  "memory order argument to atomic operation is invalid">,
+  InGroup<DiagGroup<"atomic-memory-ordering">>;
 
 def err_atomic_load_store_uses_lib : Error<
   "atomic %select{load|store}0 requires runtime support that is not "
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 19e61b2e819..30a872fcab5 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -1231,9 +1231,9 @@ ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
     llvm::APSInt Result(32);
     if (SubExprs[1]->isIntegerConstantExpr(Result, Context) &&
         !isValidOrderingForOp(Result.getSExtValue(), Op))
-      return ExprError(Diag(SubExprs[1]->getLocStart(),
-                            diag::err_atomic_op_has_invalid_memory_order)
-                       << SubExprs[1]->getSourceRange());
+      Diag(SubExprs[1]->getLocStart(),
+           diag::warn_atomic_op_has_invalid_memory_order)
+          << SubExprs[1]->getSourceRange();
   }
 
   AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
diff --git a/clang/test/Sema/atomic-ops.c b/clang/test/Sema/atomic-ops.c
index ec0a2bfe64c..6f9f568503c 100644
--- a/clang/test/Sema/atomic-ops.c
+++ b/clang/test/Sema/atomic-ops.c
@@ -187,18 +187,18 @@ void memory_checks(_Atomic(int) *Ap, int *p, int val) {
   (void)__c11_atomic_load(Ap, memory_order_relaxed);
   (void)__c11_atomic_load(Ap, memory_order_acquire);
   (void)__c11_atomic_load(Ap, memory_order_consume);
-  (void)__c11_atomic_load(Ap, memory_order_release); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__c11_atomic_load(Ap, memory_order_acq_rel); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_load(Ap, memory_order_release); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_load(Ap, memory_order_acq_rel); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__c11_atomic_load(Ap, memory_order_seq_cst);
   (void)__c11_atomic_load(Ap, val);
-  (void)__c11_atomic_load(Ap, -1); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__c11_atomic_load(Ap, 42); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_load(Ap, -1); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_load(Ap, 42); // expected-warning {{memory order argument to atomic operation is invalid}}
 
   (void)__c11_atomic_store(Ap, val, memory_order_relaxed);
-  (void)__c11_atomic_store(Ap, val, memory_order_acquire); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__c11_atomic_store(Ap, val, memory_order_consume); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_store(Ap, val, memory_order_acquire); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_store(Ap, val, memory_order_consume); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__c11_atomic_store(Ap, val, memory_order_release);
-  (void)__c11_atomic_store(Ap, val, memory_order_acq_rel); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__c11_atomic_store(Ap, val, memory_order_acq_rel); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__c11_atomic_store(Ap, val, memory_order_seq_cst);
 
   (void)__c11_atomic_fetch_add(Ap, 1, memory_order_relaxed);
@@ -267,29 +267,29 @@ void memory_checks(_Atomic(int) *Ap, int *p, int val) {
   (void)__atomic_load_n(p, memory_order_relaxed);
   (void)__atomic_load_n(p, memory_order_acquire);
   (void)__atomic_load_n(p, memory_order_consume);
-  (void)__atomic_load_n(p, memory_order_release); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__atomic_load_n(p, memory_order_acq_rel); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_load_n(p, memory_order_release); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_load_n(p, memory_order_acq_rel); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__atomic_load_n(p, memory_order_seq_cst);
 
   (void)__atomic_load(p, p, memory_order_relaxed);
   (void)__atomic_load(p, p, memory_order_acquire);
   (void)__atomic_load(p, p, memory_order_consume);
-  (void)__atomic_load(p, p, memory_order_release); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__atomic_load(p, p, memory_order_acq_rel); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_load(p, p, memory_order_release); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_load(p, p, memory_order_acq_rel); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__atomic_load(p, p, memory_order_seq_cst);
 
   (void)__atomic_store(p, p, memory_order_relaxed);
-  (void)__atomic_store(p, p, memory_order_acquire); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__atomic_store(p, p, memory_order_consume); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_store(p, p, memory_order_acquire); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_store(p, p, memory_order_consume); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__atomic_store(p, p, memory_order_release);
-  (void)__atomic_store(p, p, memory_order_acq_rel); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_store(p, p, memory_order_acq_rel); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__atomic_store(p, p, memory_order_seq_cst);
 
   (void)__atomic_store_n(p, val, memory_order_relaxed);
-  (void)__atomic_store_n(p, val, memory_order_acquire); // expected-error {{memory order argument to atomic operation is invalid}}
-  (void)__atomic_store_n(p, val, memory_order_consume); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_store_n(p, val, memory_order_acquire); // expected-warning {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_store_n(p, val, memory_order_consume); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__atomic_store_n(p, val, memory_order_release);
-  (void)__atomic_store_n(p, val, memory_order_acq_rel); // expected-error {{memory order argument to atomic operation is invalid}}
+  (void)__atomic_store_n(p, val, memory_order_acq_rel); // expected-warning {{memory order argument to atomic operation is invalid}}
   (void)__atomic_store_n(p, val, memory_order_seq_cst);
 
   (void)__atomic_fetch_add(p, val, memory_order_relaxed);