Index: lib/Transforms/InstCombine/InstCombineCalls.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -527,6 +527,13 @@
     if (Changed) return II;
   }
 
+  auto SimplifyDemandedVectorEltsLow = [this](Value *Op, unsigned Width, unsigned DemandedWidth)
+  {
+    APInt UndefElts(Width, 0);
+    APInt DemandedElts = APInt::getLowBitsSet(Width, DemandedWidth);
+    return SimplifyDemandedVectorElts(Op, DemandedElts, UndefElts);
+  };
+
   switch (II->getIntrinsicID()) {
   default: break;
   case Intrinsic::objectsize: {
@@ -975,6 +982,54 @@
       return ReplaceInstUsesWith(*II, V);
     break;
 
+  case Intrinsic::x86_sse4a_extrq: {
+    // EXTRQ uses only the lowest 64-bits of the first 128-bit vector
+    // operands and the lowest 16-bits of the second.
+    Value *Op0 = II->getArgOperand(0);
+    Value *Op1 = II->getArgOperand(1);
+    unsigned VWidth0 = Op0->getType()->getVectorNumElements();
+    unsigned VWidth1 = Op1->getType()->getVectorNumElements();
+    assert(VWidth0 == 2 && VWidth1 == 16 && "Unexpected operand sizes");
+
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op0, VWidth0, 1)) {
+      II->setArgOperand(0, V);
+      return II;
+    }
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op1, VWidth1, 2)) {
+      II->setArgOperand(1, V);
+      return II;
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse4a_extrqi: {
+    // EXTRQI uses only the lowest 64-bits of the first 128-bit vector
+    // operand.
+    Value *Op = II->getArgOperand(0);
+    unsigned VWidth = Op->getType()->getVectorNumElements();
+    assert(VWidth == 2 && "Unexpected operand size");
+
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op, VWidth, 1)) {
+      II->setArgOperand(0, V);
+      return II;
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse4a_insertq: {
+    // INSERTQ uses only the lowest 64-bits of the first 128-bit vector
+    // operand.
+    Value *Op = II->getArgOperand(0);
+    unsigned VWidth = Op->getType()->getVectorNumElements();
+    assert(VWidth == 2 && "Unexpected operand size");
+
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op, VWidth, 1)) {
+      II->setArgOperand(0, V);
+      return II;
+    }
+    break;
+  }
+
   case Intrinsic::x86_sse4a_insertqi: {
     // insertqi x, y, 64, 0 can just copy y's lower bits and leave the top
     // ones undef
@@ -1051,6 +1106,24 @@
         }
       }
     }
+
+    // INSERTQI uses only the lowest 64-bits of the first two 128-bit vector
+    // operands.
+    Value *Op0 = II->getArgOperand(0);
+    Value *Op1 = II->getArgOperand(1);
+    unsigned VWidth0 = Op0->getType()->getVectorNumElements();
+    unsigned VWidth1 = Op1->getType()->getVectorNumElements();
+    assert(VWidth0 == 2 && VWidth1 == 2 && "Unexpected operand sizes");
+
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op0, VWidth0, 1)) {
+      II->setArgOperand(0, V);
+      return II;
+    }
+
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op1, VWidth1, 1)) {
+      II->setArgOperand(1, V);
+      return II;
+    }
     break;
   }
 
Index: lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -412,7 +412,7 @@
     Value *LHS, *RHS;
     if (matchSelectPattern(I, LHS, RHS).Flavor != SPF_UNKNOWN)
       return nullptr;
-      
+
     if (SimplifyDemandedBits(I->getOperandUse(2), DemandedMask, RHSKnownZero,
                              RHSKnownOne, Depth + 1) ||
         SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, LHSKnownZero,
@@ -1237,6 +1237,15 @@
       // like undef&0.  The result is known zero, not undef.
       UndefElts &= UndefElts2;
       break;
+
+    // SSE4A instructions leave the upper 64-bits of the 128-bit result
+    // in an undefined state.
+    case Intrinsic::x86_sse4a_extrq:
+    case Intrinsic::x86_sse4a_extrqi:
+    case Intrinsic::x86_sse4a_insertq:
+    case Intrinsic::x86_sse4a_insertqi:
+      UndefElts |= APInt::getHighBitsSet(VWidth, VWidth / 2);
+      break;
     }
     break;
   }
Index: test/Transforms/InstCombine/x86-sse4a.ll
===================================================================
--- test/Transforms/InstCombine/x86-sse4a.ll
+++ test/Transforms/InstCombine/x86-sse4a.ll
@@ -121,5 +121,124 @@
   ret <2 x i64> %1
 }
 
+;
+; Vector Demanded Bits
+;
+
+define <2 x i64> @test_extrq_arg0(<2 x i64> %x, <16 x i8> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_extrq_arg0
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %x, <16 x i8> %y)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %x, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %1, <16 x i8> %y) nounwind
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_extrq_arg1(<2 x i64> %x, <16 x i8> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_extrq_arg1
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %x, <16 x i8> %y)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <16 x i8> %y, <16 x i8> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0>
+  %2 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %x, <16 x i8> %1) nounwind
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_extrq_args01(<2 x i64> %x, <16 x i8> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_extrq_args01
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %x, <16 x i8> %y)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %x, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = shufflevector <16 x i8> %y, <16 x i8> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0>
+  %3 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %1, <16 x i8> %2) nounwind
+  ret <2 x i64> %3
+}
+
+define <2 x i64> @test_extrq_ret(<2 x i64> %x, <16 x i8> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_extrq_ret
+; CHECK-NEXT: ret <2 x i64> undef
+  %1 = tail call <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64> %x, <16 x i8> %y) nounwind
+  %2 = shufflevector <2 x i64> %1, <2 x i64> undef, <2 x i32> <i32 1, i32 1>
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_extrqi_arg0(<2 x i64> %x) nounwind uwtable ssp {
+; CHECK-LABEL: @test_extrqi_arg0
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.extrqi(<2 x i64> %x, i8 3, i8 2)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %x, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = tail call <2 x i64> @llvm.x86.sse4a.extrqi(<2 x i64> %1, i8 3, i8 2)
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_extrqi_ret(<2 x i64> %x) nounwind uwtable ssp {
+; CHECK-LABEL: @test_extrqi_ret
+; CHECK-NEXT: ret <2 x i64> undef
+  %1 = tail call <2 x i64> @llvm.x86.sse4a.extrqi(<2 x i64> %x, i8 3, i8 2) nounwind
+  %2 = shufflevector <2 x i64> %1, <2 x i64> undef, <2 x i32> <i32 1, i32 1>
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_insertq_arg0(<2 x i64> %x, <2 x i64> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_insertq_arg0
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.insertq(<2 x i64> %x, <2 x i64> %y)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %x, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = tail call <2 x i64> @llvm.x86.sse4a.insertq(<2 x i64> %1, <2 x i64> %y) nounwind
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_insertq_ret(<2 x i64> %x, <2 x i64> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_insertq_ret
+; CHECK-NEXT: ret <2 x i64> undef
+  %1 = tail call <2 x i64> @llvm.x86.sse4a.insertq(<2 x i64> %x, <2 x i64> %y) nounwind
+  %2 = shufflevector <2 x i64> %1, <2 x i64> undef, <2 x i32> <i32 1, i32 1>
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_insertqi_arg0(<2 x i64> %x, <2 x i64> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_insertqi_arg0
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %x, <2 x i64> %y, i8 3, i8 2)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %x, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %1, <2 x i64> %y, i8 3, i8 2) nounwind
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_insertqi_arg1(<2 x i64> %x, <2 x i64> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_insertqi_arg1
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %x, <2 x i64> %y, i8 3, i8 2)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %y, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %x, <2 x i64> %1, i8 3, i8 2) nounwind
+  ret <2 x i64> %2
+}
+
+define <2 x i64> @test_insertqi_args01(<2 x i64> %x, <2 x i64> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_insertqi_args01
+; CHECK-NEXT: %1 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %x, <2 x i64> %y, i8 3, i8 2)
+; CHECK-NEXT: ret <2 x i64> %1
+  %1 = shufflevector <2 x i64> %x, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %2 = shufflevector <2 x i64> %y, <2 x i64> undef, <2 x i32> <i32 0, i32 0>
+  %3 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %1, <2 x i64> %2, i8 3, i8 2) nounwind
+  ret <2 x i64> %3
+}
+
+define <2 x i64> @test_insertqi_ret(<2 x i64> %x, <2 x i64> %y) nounwind uwtable ssp {
+; CHECK-LABEL: @test_insertqi_ret
+; CHECK-NEXT: ret <2 x i64> undef
+  %1 = tail call <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64> %x, <2 x i64> %y, i8 3, i8 2) nounwind
+  %2 = shufflevector <2 x i64> %1, <2 x i64> undef, <2 x i32> <i32 1, i32 1>
+  ret <2 x i64> %2
+}
+
+; CHECK: declare <2 x i64> @llvm.x86.sse4a.extrq
+declare <2 x i64> @llvm.x86.sse4a.extrq(<2 x i64>, <16 x i8>) nounwind
+
+; CHECK: declare <2 x i64> @llvm.x86.sse4a.extrqi
+declare <2 x i64> @llvm.x86.sse4a.extrqi(<2 x i64>, i8, i8) nounwind
+
+; CHECK: declare <2 x i64> @llvm.x86.sse4a.insertq
+declare <2 x i64> @llvm.x86.sse4a.insertq(<2 x i64>, <2 x i64>) nounwind
+
 ; CHECK: declare <2 x i64> @llvm.x86.sse4a.insertqi
 declare <2 x i64> @llvm.x86.sse4a.insertqi(<2 x i64>, <2 x i64>, i8, i8) nounwind