diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index 8f406a8..0112bc1 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -583,7 +583,13 @@
   } else if (SD->getKind() == SDDbgValue::CONST) {
     const Value *V = SD->getConst();
     if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
-      MIB.addImm(CI->getSExtValue());
+      // FIXME: SDDbgValues aren't updated with legalization, so it's possible
+      // to have i128 values in them at this point. As a crude workaround, just
+      // drop the debug info if this happens.
+      if (!CI->getValue().isSignedIntN(64))
+        MIB.addReg(0U);
+      else
+        MIB.addImm(CI->getSExtValue());
     } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
       MIB.addFPImm(CF);
     } else {
diff --git a/test/CodeGen/Generic/legalize-dbg-value.ll b/test/CodeGen/Generic/legalize-dbg-value.ll
new file mode 100644
index 0000000..b71aa8a
--- /dev/null
+++ b/test/CodeGen/Generic/legalize-dbg-value.ll
@@ -0,0 +1,25 @@
+; RUN: llc < %s -o /dev/null
+
+; llvm.dbg.value instructions can have types which are not legal for the
+; target. CodeGen should handle this.
+
+define i128 @__mulvti3(i128 %a, i128 %b) nounwind {
+entry:
+  tail call void @llvm.dbg.value(metadata !0, i64 0, metadata !1), !dbg !11
+  unreachable
+}
+
+declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
+
+!0 = metadata !{i128 170141183460469231731687303715884105727} 
+!1 = metadata !{i32 524544, metadata !2, metadata !"MAX", metadata !4, i32 29, metadata !8} ; [ DW_TAG_auto_variable ]
+!2 = metadata !{i32 524299, metadata !3, i32 26, i32 0} ; [ DW_TAG_lexical_block ]
+!3 = metadata !{i32 524334, i32 0, metadata !4, metadata !"__mulvti3", metadata !"__mulvti3", metadata !"__mulvti3", metadata !4, i32 26, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i1 false} ; [ DW_TAG_subprogram ]
+!4 = metadata !{i32 524329, metadata !"mulvti3.c", metadata !"/Volumes/Sandbox/llvm/swb/Libcompiler_rt-6.roots/Libcompiler_rt-6/lib", metadata !5} ; [ DW_TAG_file_type ]
+!5 = metadata !{i32 524305, i32 0, i32 1, metadata !"mulvti3.c", metadata !"/Volumes/Sandbox/llvm/swb/Libcompiler_rt-6.roots/Libcompiler_rt-6/lib", metadata !"4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2328)", i1 true, i1 true, metadata !"", i32 0} ; [ DW_TAG_compile_unit ]
+!6 = metadata !{i32 524309, metadata !4, metadata !"", metadata !4, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null} ; [ DW_TAG_subroutine_type ]
+!7 = metadata !{metadata !8, metadata !8, metadata !8}
+!8 = metadata !{i32 524310, metadata !4, metadata !"ti_int", metadata !9, i32 78, i64 0, i64 0, i64 0, i32 0, metadata !10} ; [ DW_TAG_typedef ]
+!9 = metadata !{i32 524329, metadata !"int_lib.h", metadata !"/Volumes/Sandbox/llvm/swb/Libcompiler_rt-6.roots/Libcompiler_rt-6/lib", metadata !5} ; [ DW_TAG_file_type ]
+!10 = metadata !{i32 524324, metadata !4, metadata !"", metadata !4, i32 0, i64 128, i64 128, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]
+!11 = metadata !{i32 29, i32 0, metadata !2, null}