Add loop pragma for Loop Distribution

Summary:
This is similar to other loop pragmas like 'vectorize'.  Currently it
only has state values: distribute(enable) and distribute(disable).  When
one of these is specified the corresponding loop metadata is generated:

  !{!"llvm.loop.distribute.enable", i1 true/false}

As a result, loop distribution will be attempted on the loop even if
Loop Distribution in not enabled globally.  Analogously, with 'disable'
distribution can be turned off for an individual loop even when the pass
is otherwise enabled.

There are some slight differences compared to the existing loop pragmas.

1. There is no 'assume_safety' variant which makes its handling slightly
different from 'vectorize'/'interleave'.

2. Unlike the existing loop pragmas, it does not have a corresponding
numeric pragma like 'vectorize' -> 'vectorize_width'.  So for the
consistency checks in CheckForIncompatibleAttributes we don't need to
check it against other pragmas.  We just need to check for duplicates of
the same pragma.

Reviewers: rsmith, dexonsmith, aaron.ballman

Subscribers: bob.wilson, cfe-commits, hfinkel

Differential Revision: http://reviews.llvm.org/D19403

llvm-svn: 272656

1 files changed, 18 insertions, 1 deletions

diff --git a/clang/test/Parser/pragma-loop.cpp b/clang/test/Parser/pragma-loop.cpp
index b9b5b41efba..f42d196ce8b 100644
--- a/clang/test/Parser/pragma-loop.cpp
+++ b/clang/test/Parser/pragma-loop.cpp
@@ -116,15 +116,27 @@ void test(int *List, int Length) {
     VList[j] = List[j];
   }
 
+#pragma clang loop distribute(enable)
+  for (int j : VList) {
+    VList[j] = List[j];
+  }
+
+#pragma clang loop distribute(disable)
+  for (int j : VList) {
+    VList[j] = List[j];
+  }
+
   test_nontype_template_param<4, 8>(List, Length);
 
 /* expected-error {{expected '('}} */ #pragma clang loop vectorize
 /* expected-error {{expected '('}} */ #pragma clang loop interleave
 /* expected-error {{expected '('}} */ #pragma clang loop unroll
+/* expected-error {{expected '('}} */ #pragma clang loop distribute
 
 /* expected-error {{expected ')'}} */ #pragma clang loop vectorize(enable
 /* expected-error {{expected ')'}} */ #pragma clang loop interleave(enable
 /* expected-error {{expected ')'}} */ #pragma clang loop unroll(full
+/* expected-error {{expected ')'}} */ #pragma clang loop distribute(enable
 
 /* expected-error {{expected ')'}} */ #pragma clang loop vectorize_width(4
 /* expected-error {{expected ')'}} */ #pragma clang loop interleave_count(4
@@ -133,8 +145,9 @@ void test(int *List, int Length) {
 /* 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 'enable', 'full' or 'disable'}} */ #pragma clang loop unroll()
+/* expected-error {{missing argument; expected 'enable' or 'disable'}} */ #pragma clang loop distribute()
 
-/* expected-error {{missing option; expected vectorize, vectorize_width, interleave, interleave_count, unroll, or unroll_count}} */ #pragma clang loop
+/* expected-error {{missing option; expected vectorize, vectorize_width, interleave, interleave_count, unroll, unroll_count, or distribute}} */ #pragma clang loop
 /* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop badkeyword
 /* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop badkeyword(enable)
 /* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop vectorize(enable) badkeyword(4)
@@ -187,6 +200,7 @@ const int VV = 4;
 /* 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 'enable', 'full' or 'disable'}} */ #pragma clang loop unroll(badidentifier)
+/* expected-error {{invalid argument; expected 'enable' or 'disable'}} */ #pragma clang loop distribute(badidentifier)
   while (i-7 < Length) {
     List[i] = i;
   }
@@ -196,6 +210,7 @@ const int VV = 4;
 /* expected-error {{expected ')'}} */ #pragma clang loop vectorize(()
 /* expected-error {{invalid argument; expected 'enable', 'assume_safety' or 'disable'}} */ #pragma clang loop interleave(*)
 /* expected-error {{invalid argument; expected 'enable', 'full' or 'disable'}} */ #pragma clang loop unroll(=)
+/* expected-error {{invalid argument; expected 'enable' or 'disable'}} */ #pragma clang loop distribute(+)
 /* 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(/)
 /* expected-error {{expected expression}} expected-error {{expected expression}} */ #pragma clang loop unroll_count(==)
@@ -232,6 +247,8 @@ const int VV = 4;
 #pragma clang loop interleave(disable)
 /* expected-error {{duplicate directives 'unroll(disable)' and 'unroll(full)'}} */ #pragma clang loop unroll(full)
 #pragma clang loop unroll(disable)
+/* expected-error {{duplicate directives 'distribute(disable)' and 'distribute(enable)'}} */ #pragma clang loop distribute(enable)
+#pragma clang loop distribute(disable)
   while (i-9 < Length) {
     List[i] = i;
   }