diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 48f270429e5a..b7b45a2473f4 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -786,7 +786,7 @@ Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const DataLayout *TD) {
   if (CI->getCalledFunction() == 0) return 0;
 
   if (Value *With = Simplifier->optimizeCall(CI))
-    return ReplaceInstUsesWith(*CI, With);
+    return CI->use_empty() ? CI : ReplaceInstUsesWith(*CI, With);
 
   return 0;
 }
diff --git a/test/Transforms/InstCombine/printf-2.ll b/test/Transforms/InstCombine/printf-2.ll
new file mode 100644
index 000000000000..466ee1c75770
--- /dev/null
+++ b/test/Transforms/InstCombine/printf-2.ll
@@ -0,0 +1,41 @@
+; Test that the printf library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello_world = constant [13 x i8] c"hello world\0A\00"
+@h = constant [2 x i8] c"h\00"
+@percent_s = constant [4 x i8] c"%s\0A\00"
+
+declare void @printf(i8*, ...)
+
+; Check simplification of printf with void return type.
+
+define void @test_simplify1() {
+; CHECK: @test_simplify1
+  %fmt = getelementptr [2 x i8]* @h, i32 0, i32 0
+  call void (i8*, ...)* @printf(i8* %fmt)
+; CHECK-NEXT: call i32 @putchar(i32 104)
+  ret void
+; CHECK-NEXT: ret void
+}
+
+define void @test_simplify2() {
+; CHECK: @test_simplify2
+  %fmt = getelementptr [13 x i8]* @hello_world, i32 0, i32 0
+  call void (i8*, ...)* @printf(i8* %fmt)
+; CHECK-NEXT: call i32 @puts(i8* getelementptr inbounds ([12 x i8]* @str, i32 0, i32 0))
+  ret void
+; CHECK-NEXT: ret void
+}
+
+define void @test_simplify6() {
+; CHECK: @test_simplify6
+  %fmt = getelementptr [4 x i8]* @percent_s, i32 0, i32 0
+  %str = getelementptr [13 x i8]* @hello_world, i32 0, i32 0
+  call void (i8*, ...)* @printf(i8* %fmt, i8* %str)
+; CHECK-NEXT: call i32 @puts(i8* getelementptr inbounds ([13 x i8]* @hello_world, i32 0, i32 0))
+  ret void
+; CHECK-NEXT: ret void
+}