diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index f2199d7730d..3881b0ee544 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1185,6 +1185,7 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
     // the test is for equality or unsigned, and all 1 bits of the const are
     // in the same partial word, see if we can shorten the load.
     if (DCI.isBeforeLegalize() &&
+        !ISD::isSignedIntSetCC(Cond) &&
         N0.getOpcode() == ISD::AND && C1 == 0 &&
         N0.getNode()->hasOneUse() &&
         isa<LoadSDNode>(N0.getOperand(0)) &&
diff --git a/test/CodeGen/X86/setcc-narrowing.ll b/test/CodeGen/X86/setcc-narrowing.ll
new file mode 100644
index 00000000000..25cb2c822c5
--- /dev/null
+++ b/test/CodeGen/X86/setcc-narrowing.ll
@@ -0,0 +1,18 @@
+; RUN: llc < %s -mtriple=i686-apple-darwin | FileCheck %s
+; PR17338
+
+@t1.global = internal global i64 -1, align 8
+
+define i32 @t1() nounwind ssp {
+entry:
+; CHECK-LABEL: t1:
+; CHECK: cmpl	$0, _t1.global
+; CHECK-NEXT: setne %al
+; CHECK-NEXT: movzbl %al, %eax
+; CHECK-NEXT: ret
+  %0 = load i64* @t1.global, align 8
+  %and = and i64 4294967295, %0
+  %cmp = icmp sgt i64 %and, 0
+  %conv = zext i1 %cmp to i32
+  ret i32 %conv
+}