Index: lib/CodeGen/CGExprScalar.cpp
===================================================================
--- lib/CodeGen/CGExprScalar.cpp
+++ lib/CodeGen/CGExprScalar.cpp
@@ -2712,8 +2712,10 @@
   // LLVM requires the LHS and RHS to be the same type: promote or truncate the
   // RHS to the same size as the LHS.
   Value *RHS = Ops.RHS;
-  if (Ops.LHS->getType() != RHS->getType())
-    RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
+  if (Ops.LHS->getType() != RHS->getType()) {
+    bool isSigned = dyn_cast<BinaryOperator>(Ops.E)->getRHS()->getType().getTypePtr()->isSignedIntegerType();
+    RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), isSigned, "sh_prom");
+  }
 
   bool SanitizeBase = CGF.SanOpts.has(SanitizerKind::ShiftBase) &&
                       Ops.Ty->hasSignedIntegerRepresentation();
Index: test/CodeGen/rhs_signed_check.c
===================================================================
--- test/CodeGen/rhs_signed_check.c
+++ test/CodeGen/rhs_signed_check.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 %s -emit-llvm -O0 -o - | FileCheck %s
+
+long long shl_long_short(long long arg1, short arg2) {
+   return (arg1 << arg2); 
+// CHECK:   %conv = sext i16 %1 to i32
+// CHECK:   %sh_prom = sext i32 %conv to i64
+// CHECK:   %shl = shl i64 %0, %sh_prom
+}