diff --git a/include/llvm/Support/PatternMatch.h b/include/llvm/Support/PatternMatch.h
index 035dcf513f7..55b4b6a74c4 100644
--- a/include/llvm/Support/PatternMatch.h
+++ b/include/llvm/Support/PatternMatch.h
@@ -57,7 +57,16 @@ struct constantint_ty {
 
   template<typename ITy>
   bool match(ITy *V) {
-    return isa<ConstantInt>(V) && cast<ConstantInt>(V)->getSExtValue() == Val;
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+      const APInt &CIV = CI->getValue();
+      if (Val > 0)
+        return CIV == Val;
+      // If Val is negative, and CI is shorter than it, truncate to the right
+      // number of bits.  If it is larger, then we have to sign extend.  Just
+      // compare their negated values.
+      return -CIV == -Val;
+    }
+    return false;
   }
 };
 
diff --git a/test/Transforms/InstCombine/2009-01-05-i128-crash.ll b/test/Transforms/InstCombine/2009-01-05-i128-crash.ll
new file mode 100644
index 00000000000..df3a760daf8
--- /dev/null
+++ b/test/Transforms/InstCombine/2009-01-05-i128-crash.ll
@@ -0,0 +1,27 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis
+; PR3235
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define hidden i128 @"\01_gfortrani_max_value"(i32 %length, i32 %signed_flag) nounwind {
+entry:
+	switch i32 %length, label %bb13 [
+		i32 1, label %bb17
+		i32 4, label %bb9
+		i32 8, label %bb5
+	]
+
+bb5:		; preds = %entry
+	%0 = icmp eq i32 %signed_flag, 0		; <i1> [#uses=1]
+	%iftmp.28.0 = select i1 %0, i128 18446744073709551615, i128 9223372036854775807		; <i128> [#uses=1]
+	ret i128 %iftmp.28.0
+
+bb9:		; preds = %entry
+	ret i128 0
+
+bb13:		; preds = %entry
+	ret i128 0
+
+bb17:		; preds = %entry
+	ret i128 0
+}