Index: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1290,31 +1290,44 @@
     if (!TTI.isProfitableToHoist(I1) || !TTI.isProfitableToHoist(I2))
       return Changed;
 
-    // For a normal instruction, we just move one to right before the branch,
-    // then replace all uses of the other with the first.  Finally, we remove
-    // the now redundant second instruction.
-    BIParent->getInstList().splice(BI->getIterator(), BB1->getInstList(), I1);
-    if (!I2->use_empty())
-      I2->replaceAllUsesWith(I1);
-    I1->andIRFlags(I2);
-    unsigned KnownIDs[] = {LLVMContext::MD_tbaa,
-                           LLVMContext::MD_range,
-                           LLVMContext::MD_fpmath,
-                           LLVMContext::MD_invariant_load,
-                           LLVMContext::MD_nonnull,
-                           LLVMContext::MD_invariant_group,
-                           LLVMContext::MD_align,
-                           LLVMContext::MD_dereferenceable,
-                           LLVMContext::MD_dereferenceable_or_null,
-                           LLVMContext::MD_mem_parallel_loop_access};
-    combineMetadata(I1, I2, KnownIDs);
-
-    // I1 and I2 are being combined into a single instruction.  Its debug
-    // location is the merged locations of the original instructions.
-    I1->applyMergedLocation(I1->getDebugLoc(), I2->getDebugLoc());
+    if (isa<DbgInfoIntrinsic>(I1) || isa<DbgInfoIntrinsic>(I2)) {
+      assert (isa<DbgInfoIntrinsic>(I1) && isa<DbgInfoIntrinsic>(I2));
+      // The debug location is an integral part of a debug info intrinsic
+      // and can't be separated from it or replaced.  Instead of attempting
+      // to merge locations, simply hoist both copies of the intrinsic.
+      BIParent->getInstList().splice(BI->getIterator(),
+                                     BB1->getInstList(), I1);
+      BIParent->getInstList().splice(BI->getIterator(),
+                                     BB2->getInstList(), I2);
+      Changed = true;
+    } else {
+      // For a normal instruction, we just move one to right before the branch,
+      // then replace all uses of the other with the first.  Finally, we remove
+      // the now redundant second instruction.
+      BIParent->getInstList().splice(BI->getIterator(),
+                                     BB1->getInstList(), I1);
+      if (!I2->use_empty())
+        I2->replaceAllUsesWith(I1);
+      I1->andIRFlags(I2);
+      unsigned KnownIDs[] = {LLVMContext::MD_tbaa,
+                             LLVMContext::MD_range,
+                             LLVMContext::MD_fpmath,
+                             LLVMContext::MD_invariant_load,
+                             LLVMContext::MD_nonnull,
+                             LLVMContext::MD_invariant_group,
+                             LLVMContext::MD_align,
+                             LLVMContext::MD_dereferenceable,
+                             LLVMContext::MD_dereferenceable_or_null,
+                             LLVMContext::MD_mem_parallel_loop_access};
+      combineMetadata(I1, I2, KnownIDs);
+
+      // I1 and I2 are being combined into a single instruction.  Its debug
+      // location is the merged locations of the original instructions.
+      I1->applyMergedLocation(I1->getDebugLoc(), I2->getDebugLoc());
 
-    I2->eraseFromParent();
-    Changed = true;
+      I2->eraseFromParent();
+      Changed = true;
+    }
 
     I1 = &*BB1_Itr++;
     I2 = &*BB2_Itr++;
Index: llvm/trunk/test/Transforms/SimplifyCFG/hoist-dbgvalue-inlined.ll
===================================================================
--- llvm/trunk/test/Transforms/SimplifyCFG/hoist-dbgvalue-inlined.ll
+++ llvm/trunk/test/Transforms/SimplifyCFG/hoist-dbgvalue-inlined.ll
@@ -0,0 +1,51 @@
+; RUN: opt -simplifycfg -S < %s | FileCheck %s
+; Verify that we don't crash due an invalid !dbg location on the hoisted llvm.dbg.value
+
+define i64 @caller(i64* %ptr, i64 %flag) !dbg !10 {
+init:
+  %v9 = icmp eq i64 %flag, 0
+  br i1 %v9, label %a, label %b
+
+; CHECK:  %vala = load i64, i64* %ptr
+; CHECK-NEXT:  call void @llvm.dbg.value(metadata i64 %vala, metadata [[MD:![0-9]*]]
+; CHECK-NEXT:  call void @llvm.dbg.value(metadata i64 %vala, metadata [[MD]]
+; CHECK-NEXT:  %valbmasked = and i64 %vala, 1
+
+a:                                              ; preds = %init
+  %vala = load i64, i64* %ptr, align 8
+  call void @llvm.dbg.value(metadata i64 %vala, metadata !8, metadata !DIExpression()), !dbg !12
+  br label %test.exit
+
+b:                                              ; preds = %init
+  %valb = load i64, i64* %ptr, align 8
+  call void @llvm.dbg.value(metadata i64 %valb, metadata !8, metadata !DIExpression()), !dbg !13
+  %valbmasked = and i64 %valb, 1
+  br label %test.exit
+
+test.exit:                                      ; preds = %a, %b
+  %retv = phi i64 [ %vala, %a ], [ %valbmasked, %b ]
+  ret i64 %retv
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #0
+
+attributes #0 = { nounwind readnone speculatable }
+
+!llvm.module.flags = !{!0}
+!llvm.dbg.cu = !{!1}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !3)
+!2 = !DIFile(filename: "optbug", directory: "")
+!3 = !{}
+!4 = distinct !DISubprogram(name: "callee", scope: !2, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !1, variables: !7)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{!8}
+!8 = !DILocalVariable(name: "var", scope: !4, file: !2, type: !9)
+!9 = !DIBasicType(name: "var_t", size: 64, encoding: DW_ATE_unsigned)
+!10 = distinct !DISubprogram(name: "caller", scope: !2, file: !2, line: 5, type: !5, isLocal: false, isDefinition: true, scopeLine: 5, isOptimized: false, unit: !1, variables: !3)
+!11 = distinct !DILocation(line: 6, scope: !10)
+!12 = !DILocation(line: 2, scope: !4, inlinedAt: !11)
+!13 = !DILocation(line: 3, scope: !4, inlinedAt: !11)