[OpenCL] Fix assertion due to blocks

A recent change caused assertion in CodeGenFunction::EmitBlockCallExpr when a block is called.

There is code

  Func = CGM.getOpenCLRuntime().getInvokeFunction(E->getCallee());
getCalleeDecl calls Expr::getReferencedDeclOfCallee, which does not handle
BlockExpr and returns nullptr, which causes isa to assert.

This patch fixes that.

Differential Revision: https://reviews.llvm.org/D58658

llvm-svn: 354893

clang/lib/AST/Expr.cpp

@@ -1358,6 +1358,8 @@ Decl *Expr::getReferencedDeclOfCallee() {
     return DRE->getDecl();
   if (MemberExpr *ME = dyn_cast<MemberExpr>(CEE))
     return ME->getMemberDecl();
+  if (auto *BE = dyn_cast<BlockExpr>(CEE))
+    return BE->getBlockDecl();
 
   return nullptr;
 }

clang/test/CodeGenOpenCL/blocks.cl

@@ -90,6 +90,12 @@ int get42() {
   return blockArgFunc(^{return 42;});
 }
 
+// COMMON-LABEL: define {{.*}}@call_block
+// call {{.*}}@__call_block_block_invoke
+int call_block() {
+  return ^int(int num) { return num; } (11);
+}
+
 // CHECK-DEBUG: !DIDerivedType(tag: DW_TAG_member, name: "__size"
 // CHECK-DEBUG: !DIDerivedType(tag: DW_TAG_member, name: "__align"