Index: llvm/lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -642,7 +642,7 @@
         isa<IndirectBrInst>(Pred->getTerminator())))
     return true;
 
-  if (BB->getTerminator() != BB->getFirstNonPHI())
+  if (BB->getTerminator() != BB->getFirstNonPHIOrDbg())
     return true;
 
   // We use a simple cost heuristic which determine skipping merging is
Index: llvm/test/Other/2007-04-24-eliminate-mostly-empty-blocks.ll
===================================================================
--- llvm/test/Other/2007-04-24-eliminate-mostly-empty-blocks.ll
+++ llvm/test/Other/2007-04-24-eliminate-mostly-empty-blocks.ll
@@ -1,4 +1,12 @@
-;RUN: opt < %s -codegenprepare -disable-output
+;RUN: opt < %s -codegenprepare -S | FileCheck %s
+
+;CHECK: define void @foo()
+;CHECK-NEXT: entry:
+;CHECK-NEXT:  ret void
+
+;CHECK: cond_next475:
+;CHECK-NEXT: br label %cond_next475
+
 
 define void @foo() {
 entry:
Index: llvm/test/Other/codegenprepare-and-debug.ll
===================================================================
--- /dev/null
+++ llvm/test/Other/codegenprepare-and-debug.ll
@@ -0,0 +1,88 @@
+; RUN: opt -codegenprepare -S < %s | FileCheck %s
+; RUN: opt -strip-debug -codegenprepare -S < %s | FileCheck %s
+; REQUIRES: x86-registered-target
+
+; In its current state, CodeGenPrepare should not optimize empty blocks after a switch
+; (See CodeGenPrepare::isMergingEmptyBlockProfitable)
+; This should also be the case when they contain debug information. (sw.bb block)
+; Check this by verifying that the switch labels remain the same
+
+; CHECK: while.cond:
+; CHECK-NEXT:  switch i32 undef, label %sw.default [
+; CHECK-NEXT:    i32 45, label %sw.bb
+; CHECK-NEXT:    i32 104, label %while.cond.lbl_crit_edge
+; CHECK-NEXT:    i32 122, label %while.cond.lbl_crit_edge
+; CHECK-NEXT:    i32 115, label %while.cond134.preheader
+; CHECK-NEXT:    i32 100, label %sw.bb29
+; CHECK-NEXT:    i32 105, label %sw.bb29
+; CHECK-NEXT:  ]
+
+; ModuleID = 'bugpoint-reduced-instructions.bc'
+source_filename = "foobar.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #0
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local void @foobar(i32* nocapture %arg0) local_unnamed_addr #1 {
+entry:
+  br label %while.cond
+
+while.cond:                                       ; preds = %entry
+  switch i32 undef, label %sw.default [
+    i32 45, label %sw.bb
+    i32 104, label %while.cond.lbl_crit_edge
+    i32 122, label %while.cond.lbl_crit_edge
+    i32 115, label %while.cond134.preheader
+    i32 100, label %sw.bb29
+    i32 105, label %sw.bb29
+  ]
+
+while.cond.lbl_crit_edge:                         ; preds = %while.cond, %while.cond
+  br label %lbl
+
+while.cond134.preheader:                          ; preds = %while.cond
+  unreachable
+
+sw.bb:                                            ; preds = %while.cond
+  call void @llvm.dbg.value(metadata i32 3, metadata !11, metadata !DIExpression()), !dbg !15
+  br label %lbl
+
+sw.bb29:                                          ; preds = %while.cond, %while.cond
+  unreachable
+
+sw.default:                                       ; preds = %while.cond
+  unreachable
+
+lbl:                                              ; preds = %sw.bb, %while.cond.lbl_crit_edge
+  %var03.1 = phi i32 [ 0, %while.cond.lbl_crit_edge ], [ 3, %sw.bb ]
+  unreachable
+}
+
+attributes #0 = { nounwind readnone speculatable }
+attributes #1 = { noinline nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!9, !10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version XXX ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, globals: !2)
+!1 = !DIFile(filename: "foobar.c", directory: "./")
+!2 = !{}
+!3 = !{!4, !5}
+!4 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)
+!6 = !DISubroutineType(types: !7)
+!7 = !{!4, !4, !8}
+!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+!9 = !{i32 2, !"Debug Info Version", i32 3}
+!10 = !{i32 1, !"wchar_size", i32 4}
+!11 = !DILocalVariable(name: "var03", scope: !12, file: !1, line: 3, type: !4)
+!12 = distinct !DISubprogram(name: "foobar", scope: !1, file: !1, line: 2, type: !13, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!13 = !DISubroutineType(types: !14)
+!14 = !{null, !5, !8}
+!15 = !DILocation(line: 4, column: 16, scope: !12)