[LoopUnroll] Clean up remarks for unroll remainder

The optimisation remarks for loop unrolling with an unrolled remainder looks something like:

test.c:7:18: remark: completely unrolled loop with 3 iterations [-Rpass=loop-unroll]
            C[i] += A[i*N+j];
                 ^
test.c:6:9: remark: unrolled loop by a factor of 4 with run-time trip count [-Rpass=loop-unroll]
        for(int j = 0; j < N; j++)
        ^
This removes the first of the two messages.

Differential revision: https://reviews.llvm.org/D38725



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316986 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Utils/UnrollLoop.h

@@ -67,7 +67,6 @@ bool UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
                                 LoopInfo *LI,
                                 ScalarEvolution *SE, DominatorTree *DT,
                                 AssumptionCache *AC,
-                                OptimizationRemarkEmitter *ORE,
                                 bool PreserveLCSSA);
 
 void computePeelCount(Loop *L, unsigned LoopSize,

lib/Transforms/Utils/LoopUnroll.cpp

@@ -427,9 +427,8 @@ LoopUnrollResult llvm::UnrollLoop(
 
   if (RuntimeTripCount && TripMultiple % Count != 0 &&
       !UnrollRuntimeLoopRemainder(L, Count, AllowExpensiveTripCount,
-                                  EpilogProfitability, UnrollRemainder,
-                                  LI, SE, DT, AC, ORE,
-                                  PreserveLCSSA)) {
+                                  EpilogProfitability, UnrollRemainder, LI, SE,
+                                  DT, AC, PreserveLCSSA)) {
     if (Force)
       RuntimeTripCount = false;
     else {
@@ -461,21 +460,23 @@ LoopUnrollResult llvm::UnrollLoop(
   if (CompletelyUnroll) {
     DEBUG(dbgs() << "COMPLETELY UNROLLING loop %" << Header->getName()
                  << " with trip count " << TripCount << "!\n");
-    ORE->emit([&]() {
-      return OptimizationRemark(DEBUG_TYPE, "FullyUnrolled", L->getStartLoc(),
-                                L->getHeader())
-             << "completely unrolled loop with " << NV("UnrollCount", TripCount)
-             << " iterations";
-    });
+    if (ORE)
+      ORE->emit([&]() {
+        return OptimizationRemark(DEBUG_TYPE, "FullyUnrolled", L->getStartLoc(),
+                                  L->getHeader())
+               << "completely unrolled loop with "
+               << NV("UnrollCount", TripCount) << " iterations";
+      });
   } else if (PeelCount) {
     DEBUG(dbgs() << "PEELING loop %" << Header->getName()
                  << " with iteration count " << PeelCount << "!\n");
-    ORE->emit([&]() {
-      return OptimizationRemark(DEBUG_TYPE, "Peeled", L->getStartLoc(),
-                                L->getHeader())
-             << " peeled loop by " << NV("PeelCount", PeelCount)
-             << " iterations";
-    });
+    if (ORE)
+      ORE->emit([&]() {
+        return OptimizationRemark(DEBUG_TYPE, "Peeled", L->getStartLoc(),
+                                  L->getHeader())
+               << " peeled loop by " << NV("PeelCount", PeelCount)
+               << " iterations";
+      });
   } else {
     auto DiagBuilder = [&]() {
       OptimizationRemark Diag(DEBUG_TYPE, "PartialUnrolled", L->getStartLoc(),
@@ -488,19 +489,23 @@ LoopUnrollResult llvm::UnrollLoop(
           << " by " << Count);
     if (TripMultiple == 0 || BreakoutTrip != TripMultiple) {
       DEBUG(dbgs() << " with a breakout at trip " << BreakoutTrip);
-      ORE->emit([&]() {
-        return DiagBuilder() << " with a breakout at trip "
-                             << NV("BreakoutTrip", BreakoutTrip);
-      });
+      if (ORE)
+        ORE->emit([&]() {
+          return DiagBuilder() << " with a breakout at trip "
+                               << NV("BreakoutTrip", BreakoutTrip);
+        });
     } else if (TripMultiple != 1) {
       DEBUG(dbgs() << " with " << TripMultiple << " trips per branch");
-      ORE->emit([&]() {
-        return DiagBuilder() << " with " << NV("TripMultiple", TripMultiple)
-                             << " trips per branch";
-      });
+      if (ORE)
+        ORE->emit([&]() {
+          return DiagBuilder() << " with " << NV("TripMultiple", TripMultiple)
+                               << " trips per branch";
+        });
     } else if (RuntimeTripCount) {
       DEBUG(dbgs() << " with run-time trip count");
-      ORE->emit([&]() { return DiagBuilder() << " with run-time trip count"; });
+      if (ORE)
+        ORE->emit(
+            [&]() { return DiagBuilder() << " with run-time trip count"; });
     }
     DEBUG(dbgs() << "!\n");
   }

lib/Transforms/Utils/LoopUnrollRuntime.cpp

@@ -540,7 +540,6 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
                                       bool UnrollRemainder,
                                       LoopInfo *LI, ScalarEvolution *SE,
                                       DominatorTree *DT, AssumptionCache *AC,
-                                      OptimizationRemarkEmitter *ORE,
                                       bool PreserveLCSSA) {
   DEBUG(dbgs() << "Trying runtime unrolling on Loop: \n");
   DEBUG(L->dump());
@@ -907,12 +906,12 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
 
   if (remainderLoop && UnrollRemainder) {
     DEBUG(dbgs() << "Unrolling remainder loop\n");
-    UnrollLoop(remainderLoop, /*Count*/Count - 1, /*TripCount*/Count - 1,
-               /*Force*/false, /*AllowRuntime*/false,
-               /*AllowExpensiveTripCount*/false, /*PreserveCondBr*/true,
-               /*PreserveOnlyFirst*/false, /*TripMultiple*/1,
-               /*PeelCount*/0, /*UnrollRemainder*/false, LI, SE, DT, AC, ORE,
-               PreserveLCSSA);
+    UnrollLoop(remainderLoop, /*Count*/ Count - 1, /*TripCount*/ Count - 1,
+               /*Force*/ false, /*AllowRuntime*/ false,
+               /*AllowExpensiveTripCount*/ false, /*PreserveCondBr*/ true,
+               /*PreserveOnlyFirst*/ false, /*TripMultiple*/ 1,
+               /*PeelCount*/ 0, /*UnrollRemainder*/ false, LI, SE, DT, AC,
+               /*ORE*/ nullptr, PreserveLCSSA);
   }
 
   NumRuntimeUnrolled++;

test/Transforms/LoopUnroll/loop-remarks.ll

@@ -1,8 +1,10 @@
 ; RUN: opt < %s -S -loop-unroll -pass-remarks=loop-unroll -unroll-count=16 2>&1 | FileCheck -check-prefix=COMPLETE-UNROLL %s
 ; RUN: opt < %s -S -loop-unroll -pass-remarks=loop-unroll -unroll-count=4 2>&1 | FileCheck -check-prefix=PARTIAL-UNROLL %s
+; RUN: opt < %s -S -loop-unroll -pass-remarks=loop-unroll -unroll-count=4 -unroll-runtime=true -unroll-remainder 2>&1 | FileCheck %s --check-prefix=RUNTIME-UNROLL
 
 ; COMPLETE-UNROLL: remark: {{.*}}: completely unrolled loop with 16 iterations
 ; PARTIAL-UNROLL: remark: {{.*}}: unrolled loop by a factor of 4
+; RUNTIME-UNROLL: remark: {{.*}}: unrolled loop by a factor of 4
 
 define i32 @sum() {
 entry:
@@ -22,4 +24,25 @@ for.end:                                          ; preds = %for.body
   ret i32 %add1
 }
 
-declare i32 @baz(i32)
+; RUNTIME-UNROLL-NOT: remark: {{.*}}: completely unrolled loop with 3 iterations
+; RUNTIME-UNROLL: remark: {{.*}}: unrolled loop by a factor of 4
+
+define i32 @runtime(i32 %n) {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %s.06 = phi i32 [ 0, %entry ], [ %add1, %for.body ]
+  %i.05 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %add = add nsw i32 %i.05, 4
+  %call = tail call i32 @baz(i32 %add) #2
+  %add1 = add nsw i32 %call, %s.06
+  %inc = add nsw i32 %i.05, 1
+  %exitcond = icmp eq i32 %inc, %n
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret i32 %add1
+}
+
+declare i32 @baz(i32)