[LV] Vectorization remark for outerloop

Reviewed By: fhahn, ABataev

Differential Revision: https://reviews.llvm.org/D150696

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -1031,6 +1031,23 @@ void reportVectorizationInfo(const StringRef Msg, const StringRef ORETag,
       << Msg);
 }
 
+/// Report successful vectorization of the loop. In case an outer loop is
+/// vectorized, prepend "outer" to the vectorization remark.
+static void reportVectorization(OptimizationRemarkEmitter *ORE, Loop *TheLoop,
+                                VectorizationFactor VF, unsigned IC) {
+  LLVM_DEBUG(debugVectorizationMessage(
+      "Vectorizing: ", TheLoop->isInnermost() ? "innermost loop" : "outer loop",
+      nullptr));
+  StringRef LoopType = TheLoop->isInnermost() ? "" : "outer ";
+  ORE->emit([&]() {
+    return OptimizationRemark(LV_NAME, "Vectorized", TheLoop->getStartLoc(),
+                              TheLoop->getHeader())
+           << "vectorized " << LoopType << "loop (vectorization width: "
+           << ore::NV("VectorizationFactor", VF.Width)
+           << ", interleaved count: " << ore::NV("InterleaveCount", IC) << ")";
+  });
+}
+
 } // end namespace llvm
 
 #ifndef NDEBUG
@@ -9591,6 +9608,8 @@ static bool processLoopInVPlanNativePath(
     LVP.executePlan(VF.Width, 1, BestPlan, LB, DT, false);
   }
 
+  reportVectorization(ORE, L, VF, 1);
+
   // Mark the loop as already vectorized to avoid vectorizing again.
   Hints.setAlreadyVectorized();
   assert(!verifyFunction(*L->getHeader()->getParent(), &dbgs()));
@@ -10156,13 +10175,7 @@ bool LoopVectorizePass::processLoop(Loop *L) {
           DisableRuntimeUnroll = true;
       }
       // Report the vectorization decision.
-      ORE->emit([&]() {
-        return OptimizationRemark(LV_NAME, "Vectorized", L->getStartLoc(),
-                                  L->getHeader())
-               << "vectorized loop (vectorization width: "
-               << NV("VectorizationFactor", VF.Width)
-               << ", interleaved count: " << NV("InterleaveCount", IC) << ")";
-      });
+      reportVectorization(ORE, L, VF, IC);
     }
 
     if (ORE->allowExtraAnalysis(LV_NAME))

llvm/test/Transforms/LoopVectorize/vplan-printing-outer-loop.ll

@@ -1,6 +1,6 @@
 ; REQUIRES: asserts
 
-; RUN: opt -passes=loop-vectorize -enable-vplan-native-path -debug -disable-output %s 2>&1 | FileCheck %s
+; RUN: opt -passes=loop-vectorize -pass-remarks=loop-vectorize -enable-vplan-native-path -debug -disable-output %s 2>&1 | FileCheck %s
 
 @arr2 = external global [8 x i64], align 16
 @arr = external global [8 x [8 x i64]], align 16
@@ -71,6 +71,8 @@ exit:
   ret void
 }
 
+; CHECK: remark: <unknown>:0:0: vectorized outer loop (vectorization width: 4, interleaved count: 1)
+
 !1 = distinct !{!1, !2, !3}
 !2 = !{!"llvm.loop.vectorize.width", i32 4}
 !3 = !{!"llvm.loop.vectorize.enable", i1 true}