diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -49487,6 +49487,29 @@
   return SDValue();
 }
 
+static SDValue combinePDEP(SDNode *N, SelectionDAG &DAG,
+                           TargetLowering::DAGCombinerInfo &DCI) {
+  MVT VT = N->getSimpleValueType(0);
+  SDValue Op0 = N->getOperand(0);
+  SDValue Op1 = N->getOperand(1);
+
+  // If the second operand is a constant, we can use the number of ones in it
+  // to determine the number of low bits read from the other input.
+  if (auto *C = dyn_cast<ConstantSDNode>(Op1)) {
+    uint64_t Count = C->getAPIntValue().countPopulation();
+
+    const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+    APInt DemandedMask(APInt::getLowBitsSet(VT.getSizeInBits(), Count));
+    if (TLI.SimplifyDemandedBits(Op0, DemandedMask, DCI)) {
+      if (N->getOpcode() != ISD::DELETED_NODE)
+        DCI.AddToWorklist(N);
+      return SDValue(N, 0);
+    }
+  }
+
+  return SDValue();
+}
+
 SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
                                              DAGCombinerInfo &DCI) const {
   SelectionDAG &DAG = DCI.DAG;
@@ -49657,6 +49680,7 @@
   case ISD::FP_ROUND:       return combineFP_ROUND(N, DAG, Subtarget);
   case X86ISD::VBROADCAST_LOAD: return combineVBROADCAST_LOAD(N, DAG, DCI);
   case X86ISD::MOVDQ2Q:     return combineMOVDQ2Q(N, DAG);
+  case X86ISD::PDEP:        return combinePDEP(N, DAG, DCI);
   }
 
   return SDValue();
diff --git a/llvm/test/CodeGen/X86/bmi2-x86_64.ll b/llvm/test/CodeGen/X86/bmi2-x86_64.ll
--- a/llvm/test/CodeGen/X86/bmi2-x86_64.ll
+++ b/llvm/test/CodeGen/X86/bmi2-x86_64.ll
@@ -44,9 +44,9 @@
 define i64 @pdep64_anyext(i32 %x)   {
 ; CHECK-LABEL: pdep64_anyext:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    movslq %edi, %rax
-; CHECK-NEXT:    movabsq $6148914691236517205, %rcx # imm = 0x5555555555555555
-; CHECK-NEXT:    pdepq %rcx, %rax, %rax
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    movabsq $6148914691236517205, %rax # imm = 0x5555555555555555
+; CHECK-NEXT:    pdepq %rax, %rdi, %rax
 ; CHECK-NEXT:    retq
   %x1 = sext i32 %x to i64
   %tmp = tail call i64 @llvm.x86.bmi.pdep.64(i64 %x1, i64 6148914691236517205)
diff --git a/llvm/test/CodeGen/X86/bmi2.ll b/llvm/test/CodeGen/X86/bmi2.ll
--- a/llvm/test/CodeGen/X86/bmi2.ll
+++ b/llvm/test/CodeGen/X86/bmi2.ll
@@ -86,9 +86,8 @@
 ;
 ; X64-LABEL: pdep32_anyext:
 ; X64:       # %bb.0:
-; X64-NEXT:    movswl %di, %eax
-; X64-NEXT:    movl $-1431655766, %ecx # imm = 0xAAAAAAAA
-; X64-NEXT:    pdepl %ecx, %eax, %eax
+; X64-NEXT:    movl $-1431655766, %eax # imm = 0xAAAAAAAA
+; X64-NEXT:    pdepl %eax, %edi, %eax
 ; X64-NEXT:    retq
   %x1 = sext i16 %x to i32
   %tmp = tail call i32 @llvm.x86.bmi.pdep.32(i32 %x1, i32 -1431655766)