Add assume_safety option for pragma loop vectorize and interleave.

Specifying #pragma clang loop vectorize(assume_safety) on a loop adds the
mem.parallel_loop_access metadata to each load/store operation in the loop. This
metadata tells loop access analysis (LAA) to skip memory dependency checking.

llvm-svn: 239572
diff --git a/clang/test/Parser/pragma-loop.cpp b/clang/test/Parser/pragma-loop.cpp
index a0213ac..6082058 100644
--- a/clang/test/Parser/pragma-loop.cpp
+++ b/clang/test/Parser/pragma-loop.cpp
@@ -130,7 +130,7 @@
 /* expected-error {{expected ')'}} */ #pragma clang loop interleave_count(4
 /* expected-error {{expected ')'}} */ #pragma clang loop unroll_count(4
 
-/* expected-error {{missing argument; expected 'enable' or 'disable'}} */ #pragma clang loop vectorize()
+/* expected-error {{missing argument; expected 'enable', 'assume_safety' or 'disable'}} */ #pragma clang loop vectorize()
 /* expected-error {{missing argument; expected an integer value}} */ #pragma clang loop interleave_count()
 /* expected-error {{missing argument; expected 'full' or 'disable'}} */ #pragma clang loop unroll()
 
@@ -184,8 +184,8 @@
     List[i] = i;
   }
 
-/* expected-error {{invalid argument; expected 'enable' or 'disable'}} */ #pragma clang loop vectorize(badidentifier)
-/* expected-error {{invalid argument; expected 'enable' or 'disable'}} */ #pragma clang loop interleave(badidentifier)
+/* expected-error {{invalid argument; expected 'enable', 'assume_safety' or 'disable'}} */ #pragma clang loop vectorize(badidentifier)
+/* expected-error {{invalid argument; expected 'enable', 'assume_safety' or 'disable'}} */ #pragma clang loop interleave(badidentifier)
 /* expected-error {{invalid argument; expected 'full' or 'disable'}} */ #pragma clang loop unroll(badidentifier)
   while (i-7 < Length) {
     List[i] = i;
@@ -194,7 +194,7 @@
 // PR20069 - Loop pragma arguments that are not identifiers or numeric
 // constants crash FE.
 /* expected-error {{expected ')'}} */ #pragma clang loop vectorize(()
-/* expected-error {{invalid argument; expected 'enable' or 'disable'}} */ #pragma clang loop interleave(*)
+/* expected-error {{invalid argument; expected 'enable', 'assume_safety' or 'disable'}} */ #pragma clang loop interleave(*)
 /* expected-error {{invalid argument; expected 'full' or 'disable'}} */ #pragma clang loop unroll(=)
 /* expected-error {{type name requires a specifier or qualifier}} expected-error {{expected expression}} */ #pragma clang loop vectorize_width(^)
 /* expected-error {{expected expression}} expected-error {{expected expression}} */ #pragma clang loop interleave_count(/)