[CodeGen] Generate llvm.loop.parallel_accesses instead of llvm.mem.parallel_loop_access metadata.

Instead of generating llvm.mem.parallel_loop_access metadata, generate
llvm.access.group on instructions and llvm.loop.parallel_accesses on
loops. There is one access group per generated loop.

This is clang part of D52116/r349725.

Differential Revision: https://reviews.llvm.org/D52117

llvm-svn: 349823
diff --git a/clang/test/OpenMP/target_simd_codegen.cpp b/clang/test/OpenMP/target_simd_codegen.cpp
index 81ad403..1350421 100644
--- a/clang/test/OpenMP/target_simd_codegen.cpp
+++ b/clang/test/OpenMP/target_simd_codegen.cpp
@@ -342,7 +342,7 @@
 // CHECK-64:    [[AA_CADDR:%.+]] = bitcast i[[SZ]]* [[AA_ADDR]] to i32*
 // CHECK-64:    [[AA:%.+]] = load i32, i32* [[AA_CADDR]], align
 // CHECK-32:    [[AA:%.+]] = load i32, i32* [[AA_ADDR]], align
-// CHECK:       !llvm.mem.parallel_loop_access
+// CHECK:       !llvm.access.group
 // CHECK:       !llvm.loop
 // CHECK:       ret void
 // CHECK-NEXT:  }