diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index ac7d18feb5b31..307908aef9784 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -752,6 +752,14 @@ llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
         }
       }
 
+      // Remap source location atom instance. Do this now, rather than
+      // when we remap instructions, because remap is called once we've
+      // cloned all blocks (all the clones would get the same atom
+      // number).
+      if (!VMap.AtomMap.empty())
+        for (Instruction &I : *New)
+          RemapSourceAtom(&I, VMap);
+
       // Update our running map of newest clones
       LastValueMap[*BB] = New;
       for (ValueToValueMapTy::iterator VI = VMap.begin(), VE = VMap.end();
@@ -802,7 +810,8 @@ llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
       }
     }
 
-    // Remap all instructions in the most recent iteration
+    // Remap all instructions in the most recent iteration.
+    // Key Instructions: Nothing to do - we've already remapped the atoms.
     remapInstructionsInBlocks(NewBlocks, LastValueMap);
     for (BasicBlock *NewBlock : NewBlocks)
       for (Instruction &I : *NewBlock)
diff --git a/llvm/test/DebugInfo/KeyInstructions/Generic/loop-unroll-runtime.ll b/llvm/test/DebugInfo/KeyInstructions/Generic/loop-unroll-runtime.ll
new file mode 100644
index 0000000000000..6deb04cc00f8d
--- /dev/null
+++ b/llvm/test/DebugInfo/KeyInstructions/Generic/loop-unroll-runtime.ll
@@ -0,0 +1,69 @@
+
+; RUN: opt %s -S --passes=loop-unroll -unroll-runtime=true -unroll-count=4 -unroll-remainder -o - \
+; RUN: | FileCheck %s
+
+;; Check atoms are remapped for runtime unrolling.
+
+; CHECK: for.body.epil:
+; CHECK-NEXT: store i64 %indvars.iv.unr, ptr %p, align 4, !dbg [[G2R1:!.*]]
+
+; CHECK: for.body.epil.1:
+; CHECK-NEXT: store i64 %indvars.iv.next.epil, ptr %p, align 4, !dbg [[G3R1:!.*]]
+
+; CHECK: for.body.epil.2:
+; CHECK-NEXT: store i64 %indvars.iv.next.epil.1, ptr %p, align 4, !dbg [[G4R1:!.*]]
+
+; CHECK: for.body:
+; CHECK-NEXT: %indvars.iv = phi i64 [ 0, %for.body.lr.ph.new ], [ %indvars.iv.next.3, %for.body ]
+; CHECK-NEXT: %niter = phi i64 [ 0, %for.body.lr.ph.new ], [ %niter.next.3, %for.body ]
+; CHECK-NEXT: store i64 %indvars.iv, ptr %p, align 4, !dbg [[G1R1:!.*]]
+; CHECK-NEXT: %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+; CHECK-NEXT: store i64 %indvars.iv.next, ptr %p, align 4, !dbg [[G5R1:!.*]]
+; CHECK-NEXT: %indvars.iv.next.1 = add nuw nsw i64 %indvars.iv, 2
+; CHECK-NEXT: store i64 %indvars.iv.next.1, ptr %p, align 4, !dbg [[G6R1:!.*]]
+; CHECK-NEXT: %indvars.iv.next.2 = add nuw nsw i64 %indvars.iv, 3
+; CHECK-NEXT: store i64 %indvars.iv.next.2, ptr %p, align 4, !dbg [[G7R1:!.*]]
+; CHECK-NEXT: %indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 4
+
+; CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
+; CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
+; CHECK: [[G4R1]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1)
+; CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
+; CHECK: [[G5R1]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1)
+; CHECK: [[G6R1]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 1)
+; CHECK: [[G7R1]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 1)
+
+define i32 @unroll(ptr %p, i32 %N) local_unnamed_addr !dbg !5 {
+entry:
+  %cmp9 = icmp eq i32 %N, 0
+  br i1 %cmp9, label %for.cond.cleanup, label %for.body.lr.ph
+
+for.body.lr.ph:                                   ; preds = %entry
+  %wide.trip.count = zext i32 %N to i64
+  br label %for.body
+
+for.cond.cleanup:                                 ; preds = %for.body, %entry
+  %r = phi i32 [ 0, %entry ], [ 1, %for.body ]
+  ret i32 %r
+
+for.body:                                         ; preds = %for.body, %for.body.lr.ph
+  %indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
+  store i64 %indvars.iv, ptr %p, !dbg !8
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, %wide.trip.count
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.debugify = !{!2, !3}
+!llvm.module.flags = !{!4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!1 = !DIFile(filename: "test.ll", directory: "/")
+!2 = !{i32 17}
+!3 = !{i32 0}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = distinct !DISubprogram(name: "unroll", linkageName: "unroll", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
+!6 = !DISubroutineType(types: !7)
+!7 = !{}
+!8 = !DILocation(line: 1, column: 1, scope: !5, atomGroup: 1, atomRank: 1)
diff --git a/llvm/test/DebugInfo/KeyInstructions/Generic/loop-unroll.ll b/llvm/test/DebugInfo/KeyInstructions/Generic/loop-unroll.ll
new file mode 100644
index 0000000000000..557e8387e5bc5
--- /dev/null
+++ b/llvm/test/DebugInfo/KeyInstructions/Generic/loop-unroll.ll
@@ -0,0 +1,48 @@
+; RUN: opt %s --passes=loop-unroll -S -o - -S | FileCheck %s
+
+; CHECK: store i32 %a, ptr %p, align 4, !dbg [[G1R1:!.*]]
+; CHECK: %v.1 = add i32 1, %a, !dbg [[G2R2:!.*]]
+; CHECK: store i32 %v.1, ptr %p, align 4, !dbg [[G2R1:!.*]]
+; CHECK: %v.2 = add i32 2, %a, !dbg [[G3R2:!.*]]
+; CHECK: store i32 %v.2, ptr %p, align 4, !dbg [[G3R1:!.*]]
+
+; CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
+; CHECK: [[G2R2]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2)
+; CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
+; CHECK: [[G3R2]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 2)
+; CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
+
+define void @f(ptr %p, i32 %a) local_unnamed_addr #0 !dbg !5 {
+entry:
+  br label %for.body
+
+for.cond.cleanup:                                 ; preds = %for.body
+  ret void
+
+for.body:                                         ; preds = %for.body, %entry
+  %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %v = add i32 %i, %a, !dbg !11
+  store i32 %v, ptr %p, align 4, !dbg !12
+  %inc = add i32 %i, 1
+  %cmp = icmp slt i32 %inc, 3
+  br i1 %cmp, label %for.body, label %for.cond.cleanup
+}
+
+declare i32 @bar(...) local_unnamed_addr
+
+attributes #0 = { nounwind ssp uwtable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.debugify = !{!2, !3}
+!llvm.module.flags = !{!4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!1 = !DIFile(filename: "/home/och/scratch/test.ll", directory: "/")
+!2 = !{i32 8}
+!3 = !{i32 0}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
+!6 = !DISubroutineType(types: !7)
+!7 = !{}
+!11 = !DILocation(line: 4, column: 1, scope: !5, atomGroup: 1, atomRank: 2)
+!12 = !DILocation(line: 5, column: 1, scope: !5, atomGroup: 1, atomRank: 1)