Index: llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -690,14 +690,14 @@
   BasicBlock::iterator IP = BB.getFirstInsertionPt();
   bool IsEntryBB = &BB == &F.getEntryBlock();
   DebugLoc EntryLoc;
+  if (auto SP = F.getSubprogram())
+    EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
   if (IsEntryBB) {
-    if (auto SP = F.getSubprogram())
-      EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
     // Keep static allocas and llvm.localescape calls in the entry block.  Even
     // if we aren't splitting the block, it's nice for allocas to be before
     // calls.
     IP = PrepareToSplitEntryBlock(BB, IP);
-  } else {
+  } else if(IP->getDebugLoc()) {
     EntryLoc = IP->getDebugLoc();
   }
 
Index: llvm/test/Instrumentation/SanitizerCoverage/coverage-dbg-pcguard.ll
===================================================================
--- /dev/null
+++ llvm/test/Instrumentation/SanitizerCoverage/coverage-dbg-pcguard.ll
@@ -0,0 +1,46 @@
+; Test that coverage instrumentation does not lose debug location.
+
+; RUN: opt < %s -sancov -sanitizer-coverage-level=4 -sanitizer-coverage-trace-pc-guard  -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @__sanitizer_cov_trace_pc_guard(i32*)  !dbg !13 {
+	ret void
+}
+
+define void @_ZN1A1fEv(i1 %cond) !dbg !13 {
+entry:
+  br i1 %cond, label %cont, label %exit
+cont:
+  br label %exit
+exit:
+  ret void, !dbg !21
+}
+
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!17, !18}
+!llvm.ident = !{!19}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5.0 (210251)", isOptimized: true, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !3, globals: !2, imports: !2)
+!1 = !DIFile(filename: "../1.cc", directory: "/code/llvm/build0")
+!2 = !{}
+!3 = !{!4}
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "A", line: 1, size: 32, align: 32, file: !1, elements: !5, identifier: "_ZTS1A")
+!5 = !{!6, !8}
+!6 = !DIDerivedType(tag: DW_TAG_member, name: "x", line: 3, size: 32, align: 32, file: !1, scope: !4, baseType: !7)
+!7 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!8 = !DISubprogram(name: "f", linkageName: "_ZN1A1fEv", line: 2, isLocal: false, isDefinition: false, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 2, file: !1, scope: !4, type: !9)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!7, !11}
+!11 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, flags: DIFlagArtificial | DIFlagObjectPointer, baseType: !4)
+!13 = distinct !DISubprogram(name: "f", linkageName: "_ZN1A1fEv", line: 6, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 6, file: !1, scope: !4, type: !9, declaration: !8, variables: !14)
+!14 = !{!15}
+!15 = !DILocalVariable(name: "this", arg: 1, flags: DIFlagArtificial | DIFlagObjectPointer, scope: !13, type: !16)
+!16 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, baseType: !4)
+!17 = !{i32 2, !"Dwarf Version", i32 4}
+!18 = !{i32 2, !"Debug Info Version", i32 3}
+!19 = !{!"clang version 3.5.0 (210251)"}
+!20 = !DILocation(line: 0, scope: !13)
+!21 = !DILocation(line: 7, scope: !13)