Index: lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
+++ lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
@@ -1005,6 +1005,16 @@
   return false;
 }
 
+static Value *getSign32(Value *V, IRBuilder<> &Builder, const DataLayout *DL) {
+  // Check whether the sign can be determined statically.
+  KnownBits Known = computeKnownBits(V, *DL);
+  if (Known.isNegative())
+    return Constant::getAllOnesValue(V->getType());
+  if (Known.isNonNegative())
+    return Constant::getNullValue(V->getType());
+  return Builder.CreateAShr(V, Builder.getInt32(31));
+}
+
 Value* AMDGPUCodeGenPrepare::expandDivRem32(IRBuilder<> &Builder,
                                             BinaryOperator &I,
                                             Value *Num, Value *Den) const {
@@ -1046,9 +1056,8 @@
 
   Value *Sign = nullptr;
   if (IsSigned) {
-    ConstantInt *K31 = Builder.getInt32(31);
-    Value *LHSign = Builder.CreateAShr(Num, K31);
-    Value *RHSign = Builder.CreateAShr(Den, K31);
+    Value *LHSign = getSign32(Num, Builder, DL);
+    Value *RHSign = getSign32(Den, Builder, DL);
     // Remainder sign is the same as LHS
     Sign = IsDiv ? Builder.CreateXor(LHSign, RHSign) : LHSign;