[SYCLomatic] Support migration dereference for std::vector subscript. (#650)

Signed-off-by: Chen, Sheng S <[email protected]>

Author: ShengchenJ

clang/lib/DPCT/CallExprRewriterCommon.h

@@ -696,6 +696,9 @@ inline std::function<std::string(const CallExpr *C)> getDerefedType(size_t Idx)
       } else if (BaseType->isPointerType()) {
         DerefQT = BaseType->getPointeeType();
       }
+    } else if (auto COCE = dyn_cast<CXXOperatorCallExpr>(TE)) {
+      // Handle cases like A[3] where A is a vector with sepecfying type.
+      DerefQT = COCE->getType().getCanonicalType();
     }
 
     // All other cases

clang/lib/DPCT/Utility.cpp

@@ -2032,6 +2032,13 @@ bool needExtraParens(const Expr *E) {
     else
       return true;
   }
+  case Stmt::CXXOperatorCallExprClass: {
+    if (auto COCE = dyn_cast<CXXOperatorCallExpr>(E)) {
+      if (COCE->getOperator() == clang::OO_Subscript)
+        return false;
+    }
+    return true;
+  }
   default:
     return true;
   }

clang/test/dpct/USM-restricted.cu

@@ -9,6 +9,7 @@
 #include <cuda.h>
 #include <stdio.h>
 #include <memory>
+#include <vector>
 
 #define MY_SAFE_CALL(CALL) do {    \
   int Error = CALL;                \
@@ -1070,3 +1071,15 @@ void foo14() {
   cudaMemcpy((void *)&h_selected_num, (void *)d_selected_num, sizeof(int), cudaMemcpyDeviceToHost);
   cudaMemcpy((void *)h_out, (void *)d_out, h_selected_num * sizeof(int), cudaMemcpyDeviceToHost);
 }
+
+struct TEST_STR {
+  int a[10];
+};
+
+void foo15() {
+  std::vector<volatile TEST_STR *> buf;
+  for (int i = 0; i < 32; i++) {
+    //CHECK: buf[i] = (volatile TEST_STR *)sycl::malloc_host(sizeof(TEST_STR), dpct::get_default_queue());
+    cudaMallocHost(&buf[i], sizeof(TEST_STR));
+  }
+}