[OpenCL] Diagnose assignment to dereference of half type pointer

Differential Revision: https://reviews.llvm.org/D24626

llvm-svn: 281904

3 files changed, 18 insertions, 3 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index af333d38601..6090fc70536 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -659,7 +659,8 @@ def err_object_cannot_be_passed_returned_by_value : Error<
 def err_parameters_retval_cannot_have_fp16_type : Error<
   "%select{parameters|function return value}0 cannot have __fp16 type; did you forget * ?">;
 def err_opencl_half_load_store : Error<
-  "%select{loading directly from|assigning directly to}0 pointer to type %1 is not allowed">;
+  "%select{loading directly from|assigning directly to}0 pointer to type %1 requires "
+  "cl_khr_fp16. Use vector data %select{load|store}0 builtin functions instead">;
 def err_opencl_cast_to_half : Error<"casting to type %0 is not allowed">;
 def err_opencl_half_declaration : Error<
   "declaring variable of type %0 is not allowed">;
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 72a35866ad6..f34263dba51 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -10100,6 +10100,16 @@ QualType Sema::CheckAssignmentOperands(Expr *LHSExpr, ExprResult &RHS,
   QualType LHSType = LHSExpr->getType();
   QualType RHSType = CompoundType.isNull() ? RHS.get()->getType() :
                                              CompoundType;
+  // OpenCL v1.2 s6.1.1.1 p2:
+  // The half data type can only be used to declare a pointer to a buffer that
+  // contains half values
+  if (getLangOpts().OpenCL && !getOpenCLOptions().cl_khr_fp16 &&
+    LHSType->isHalfType()) {
+    Diag(Loc, diag::err_opencl_half_load_store) << 1
+        << LHSType.getUnqualifiedType();
+    return QualType();
+  }
+    
   AssignConvertType ConvTy;
   if (CompoundType.isNull()) {
     Expr *RHSCheck = RHS.get();
diff --git a/clang/test/SemaOpenCL/half.cl b/clang/test/SemaOpenCL/half.cl
index dd7bb9ab8c5..fe88cf1b954 100644
--- a/clang/test/SemaOpenCL/half.cl
+++ b/clang/test/SemaOpenCL/half.cl
@@ -8,8 +8,10 @@ half half_disabled(half *p, // expected-error{{declaring function return value o
 {
   half a[2]; // expected-error{{declaring variable of type 'half [2]' is not allowed}}
   half b;    // expected-error{{declaring variable of type 'half' is not allowed}}
-  *p; // expected-error{{loading directly from pointer to type 'half' is not allowed}}
-  p[1]; // expected-error{{loading directly from pointer to type 'half' is not allowed}}
+  *p; // expected-error{{loading directly from pointer to type 'half' requires cl_khr_fp16. Use vector data load builtin functions instead}}
+  *p = 0; // expected-error{{assigning directly to pointer to type 'half' requires cl_khr_fp16. Use vector data store builtin functions instead}}
+  p[1]; // expected-error{{loading directly from pointer to type 'half' requires cl_khr_fp16. Use vector data load builtin functions instead}}
+  p[1] = 0; // expected-error{{assigning directly to pointer to type 'half' requires cl_khr_fp16. Use vector data store builtin functions instead}}
 
   float c = 1.0f;
   b = (half) c;  // expected-error{{casting to type 'half' is not allowed}}
@@ -31,7 +33,9 @@ half half_enabled(half *p, half h)
   half a[2];
   half b;
   *p;
+  *p = 0;
   p[1];
+  p[1] = 0;
 
   float c = 1.0f;
   b = (half) c;