Index: lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- lib/Transforms/Utils/SimplifyCFG.cpp
+++ lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1242,6 +1242,14 @@
                            LLVMContext::MD_dereferenceable_or_null,
                            LLVMContext::MD_mem_parallel_loop_access};
     combineMetadata(I1, I2, KnownIDs);
+
+    // If the debug loc for I1 and I2 are different, as we are combining them
+    // into one instruction, we do not want to select debug loc randomly from 
+    // I1 or I2. Instead, we set the 0-line DebugLoc to note that we do not
+    // know the debug loc of the hoisted instruction.
+    if (!isa<CallInst>(I1) &&  I1->getDebugLoc() != I2->getDebugLoc())
+      I1->setDebugLoc(DebugLoc());
+ 
     I2->eraseFromParent();
     Changed = true;
 
Index: test/Transforms/SimplifyCFG/remove-debug.ll
===================================================================
--- /dev/null
+++ test/Transforms/SimplifyCFG/remove-debug.ll
@@ -0,0 +1,83 @@
+; RUN: opt < %s -simplifycfg -S | FileCheck %s
+
+; TODO: Track the acutal DebugLoc of the hoisted instruction when no-line
+; DebugLoc is supported (https://reviews.llvm.org/D24180)
+; CHECK: line: 6
+; CHECK-NOT: line: 7
+; CHECK: line: 8
+; CHECK: line: 9
+; CHECK-NOT: line: 10
+; CHECK: line: 11
+
+; Checks if the debug info for hoisted "x = i" is removed
+; int x;
+; void bar();
+; void baz();
+;
+; void foo(int i) {
+;   if (i == 0) {
+;     x = i;
+;     bar();
+;   } else {
+;     x = i;
+;     baz();
+;   }
+; }
+
+target triple = "x86_64-unknown-linux-gnu"
+
+@x = global i32 0, align 4
+
+; Function Attrs: uwtable
+define void @_Z3fooi(i32) #0 !dbg !6 {
+  %2 = alloca i32, align 4
+  store i32 %0, i32* %2, align 4, !tbaa !8
+  %3 = load i32, i32* %2, align 4, !dbg !12, !tbaa !8
+  %4 = icmp eq i32 %3, 0, !dbg !13
+  br i1 %4, label %5, label %7, !dbg !12
+
+; <label>:5:
+  %6 = load i32, i32* %2, align 4, !dbg !14, !tbaa !8
+  store i32 %6, i32* @x, align 4, !dbg !15, !tbaa !8
+  call void @_Z3barv(), !dbg !16
+  br label %9, !dbg !17
+
+; <label>:7:
+  %8 = load i32, i32* %2, align 4, !dbg !18, !tbaa !8
+  store i32 %8, i32* @x, align 4, !dbg !19, !tbaa !8
+  call void @_Z3bazv(), !dbg !20
+  br label %9
+
+; <label>:9:
+  ret void, !dbg !21
+}
+
+declare void @_Z3barv() #1
+
+declare void @_Z3bazv() #1
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1)
+!1 = !DIFile(filename: "a", directory: "b/")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{}
+!6 = distinct !DISubprogram(unit: !0)
+!7 = !DISubroutineType(types: !2)
+!8 = !{!9, !9, i64 0}
+!9 = !{!"int", !10, i64 0}
+!10 = !{!"omnipotent char", !11, i64 0}
+!11 = !{!"Simple C++ TBAA"}
+!12 = !DILocation(line: 6, column: 7, scope: !6)
+!13 = !DILocation(line: 6, column: 9, scope: !6)
+!14 = !DILocation(line: 7, column: 9, scope: !6)
+!15 = !DILocation(line: 7, column: 7, scope: !6)
+!16 = !DILocation(line: 8, column: 5, scope: !6)
+!17 = !DILocation(line: 9, column: 3, scope: !6)
+!18 = !DILocation(line: 10, column: 9, scope: !6)
+!19 = !DILocation(line: 10, column: 7, scope: !6)
+!20 = !DILocation(line: 11, column: 5, scope: !6)
+!21 = !DILocation(line: 13, column: 1, scope: !6)