[PATCH] D48808: [CodeGen] Emit parallel_loop_access for each loop in the loop stack.

[Michael Kruse via Phabricator via cfe-commits]

Meinersbur created this revision.
Meinersbur added reviewers: ABataev, hfinkel.

Emit !llvm.mem.parallel_loop_access metadata for memory accesses even if the parallel loop is not the top on the loop stack.

Fixes llvm.org/PR37558.


Repository:
  rC Clang

https://reviews.llvm.org/D48808

Files:
  lib/CodeGen/CGLoopInfo.cpp
  test/CodeGenCXX/pragma-loop-safety-nested.cpp


Index: test/CodeGenCXX/pragma-loop-safety-nested.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/pragma-loop-safety-nested.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++11 -emit-llvm -o - %s | FileCheck %s
+
+// Verify that the inner access is tagged with a parallel_loop_access
+// for the outer loop.
+void vectorize_nested_test(int *List, int Length) {
+#pragma clang loop vectorize(assume_safety) interleave(disable) unroll(disable)
+  for (int i = 0; i < Length; i += 2) {
+#pragma clang loop unroll(full)
+    for (int j = 0; j < 2; j += 1)
+      List[i + j] = (i + j) * 2;
+  }
+}
+
+// CHECK: %[[MUL:.+]] = mul
+// CHECK: store i32 %[[MUL]], i32* %{{.+}}, !llvm.mem.parallel_loop_access ![[OUTER_LOOPID:[0-9]+]]
+// CHECK: br label %{{.+}}, !llvm.loop ![[INNER_LOOPID:[0-9]+]]
+// CHECK: br label %{{.+}}, !llvm.loop ![[OUTER_LOOPID]]
+
+// CHECK: ![[OUTER_LOOPID]] = distinct !{![[OUTER_LOOPID]],
+// CHECK: ![[INNER_LOOPID]] = distinct !{![[INNER_LOOPID]],
Index: lib/CodeGen/CGLoopInfo.cpp
===================================================================
--- lib/CodeGen/CGLoopInfo.cpp
+++ lib/CodeGen/CGLoopInfo.cpp
@@ -300,6 +300,7 @@
     return;
   }
 
-  if (L.getAttributes().IsParallel && I->mayReadOrWriteMemory())
-    I->setMetadata("llvm.mem.parallel_loop_access", L.getLoopID());
+  for (const LoopInfo &AL : Active)
+    if (AL.getAttributes().IsParallel && I->mayReadOrWriteMemory())
+      I->setMetadata("llvm.mem.parallel_loop_access", AL.getLoopID());
 }


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