[PATCH] D49458: Support implicit _Atomic struct load / store

[JF Bastien via Phabricator via cfe-commits]

jfb created this revision.
jfb added a reviewer: dexonsmith.
Herald added a subscriber: cfe-commits.

Using _Atomic to do implicit load / store is just a seq_cst atomic_load / atomic_store. Stores currently assert in Sema::ImpCastExprToType with 'can't implicitly cast lvalue to rvalue with this cast kind', but that's erroneous. The codegen is fine as the test shows.

While investigating I found that Richard had found the problem here: https://reviews.llvm.org/D46112#1113557

rdar://problem/40347123


Repository:
  rC Clang

https://reviews.llvm.org/D49458

Files:
  lib/Sema/Sema.cpp
  test/CodeGen/atomic-ops.c


Index: test/CodeGen/atomic-ops.c
===================================================================
--- test/CodeGen/atomic-ops.c
+++ test/CodeGen/atomic-ops.c
@@ -183,6 +183,18 @@
   double x;
 };
 
+void implicit_store(_Atomic(struct S) *a, struct S s) {
+  // CHECK-LABEL: @implicit_store(
+  // CHECK: store atomic i64 %{{.*}}, i64* %{{.*}} seq_cst, align 8
+  *a = s;
+}
+
+struct S implicit_load(_Atomic(struct S) *a) {
+  // CHECK-LABEL: @implicit_load(
+  // CHECK: load atomic i64, i64* %{{.*}} seq_cst, align 8
+  return *a;
+}
+
 struct S fd1(struct S *a) {
   // CHECK-LABEL: @fd1
   // CHECK: [[RETVAL:%.*]] = alloca %struct.S, align 4
Index: lib/Sema/Sema.cpp
===================================================================
--- lib/Sema/Sema.cpp
+++ lib/Sema/Sema.cpp
@@ -481,6 +481,7 @@
     case CK_ArrayToPointerDecay:
     case CK_FunctionToPointerDecay:
     case CK_ToVoid:
+    case CK_NonAtomicToAtomic:
       break;
     }
   }


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