[SYCL] Fix crash in clang for SYCL kernels with accessors and SC

In case a SYCL kernel captures specialization constants and more then
one accessor it crashes. I think the crash happens due to an extra
increment of KernelFuncParam, in CreateOpenCLKernelBody() method.

Signed-off-by: Alexey Sotkin <alexey.sotkin@intel.com>

Author: AlexeySotkin

clang/lib/Sema/SemaSYCL.cpp

@@ -815,6 +815,7 @@ static CompoundStmt *CreateOpenCLKernelBody(Sema &S,
                                  InitMethodName, BodyStmts);
       } else if (Util::isSyclSpecConstantType(FieldType)) {
         // Just skip specialization constants - not part of signature.
+        continue;
       } else if (CRD || FieldType->isScalarType()) {
         // If field has built-in or a structure/class type just initialize
         // this field with corresponding kernel argument using copy

sycl/test/spec_const/spec_const_accesors.cpp

@@ -0,0 +1,46 @@
+// RUN: %clangxx -fsycl-device-only %s -o %t.bc
+//
+//==----------- spec_const_accessors.cpp -----------------------------------==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// The test checks that Clang doesn't crash if multiple accessors are used
+// together with specialization constants in single kernel.
+
+#include <CL/sycl.hpp>
+
+using namespace sycl;
+
+class MyInt32Const;
+class MyKernel;
+
+int32_t val = 10;
+
+int main() {
+  cl::sycl::queue queue;
+  cl::sycl::program program(queue.get_context());
+
+  cl::sycl::experimental::spec_constant<int32_t, MyInt32Const> i32 =
+      program.set_spec_constant<MyInt32Const>(val);
+
+  program.build_with_kernel_type<MyKernel>();
+  int32_t a = 0;
+  int32_t b = 0;
+  cl::sycl::buffer<int32_t, 1> buf_a(&a, 1);
+  cl::sycl::buffer<int32_t, 1> buf_b(&b, 1);
+
+  queue.submit([&](cl::sycl::handler &cgh) {
+    auto acc_a = buf_a.get_access<cl::sycl::access::mode::write>(cgh);
+    auto acc_b = buf_b.get_access<cl::sycl::access::mode::write>(cgh);
+    cgh.single_task<MyKernel>(
+        program.get_kernel<MyKernel>(),
+        [=]() {
+          acc_a[0] = i32.get();
+          acc_b[0] = i32.get();
+        });
+  });
+  return 0;
+}