Index: llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp
===================================================================
--- llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp
+++ llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp
@@ -998,6 +998,20 @@
         return IC.replaceInstUsesWith(II, II.getArgOperand(0));
       }
 
+      if (MaskC->getValue().isShiftedMask()) {
+        // any single contingous sequence of 1s anywhere in the mask simply
+        // describes a subset of the input bits shifted to the appropriate
+        // position.  Replace with the straight forward IR.
+        unsigned ShiftAmount = MaskC->getValue().countTrailingZeros();
+        Value *Input = II.getArgOperand(0);
+        Value *Masked = IC.Builder.CreateAnd(Input, II.getArgOperand(1));
+        Value *Shifted = IC.Builder.CreateLShr(Masked,
+                                               ConstantInt::get(II.getType(),
+                                                                ShiftAmount));
+        return IC.replaceInstUsesWith(II, Shifted);
+      }
+
+
       if (auto *SrcC = dyn_cast<ConstantInt>(II.getArgOperand(0))) {
         uint64_t Src = SrcC->getZExtValue();
         uint64_t Mask = MaskC->getZExtValue();
@@ -1029,6 +1043,18 @@
       if (MaskC->isAllOnesValue()) {
         return IC.replaceInstUsesWith(II, II.getArgOperand(0));
       }
+      if (MaskC->getValue().isShiftedMask()) {
+        // any single contingous sequence of 1s anywhere in the mask simply
+        // describes a subset of the input bits shifted to the appropriate
+        // position.  Replace with the straight forward IR.
+        unsigned ShiftAmount = MaskC->getValue().countTrailingZeros();
+        Value *Input = II.getArgOperand(0);
+        Value *Shifted = IC.Builder.CreateShl(Input,
+                                              ConstantInt::get(II.getType(),
+                                                               ShiftAmount));
+        Value *Masked = IC.Builder.CreateAnd(Shifted, II.getArgOperand(1));
+        return IC.replaceInstUsesWith(II, Masked);
+      }
 
       if (auto *SrcC = dyn_cast<ConstantInt>(II.getArgOperand(0))) {
         uint64_t Src = SrcC->getZExtValue();
Index: llvm/test/Transforms/InstCombine/X86/x86-bmi-tbm.ll
===================================================================
--- llvm/test/Transforms/InstCombine/X86/x86-bmi-tbm.ll
+++ llvm/test/Transforms/InstCombine/X86/x86-bmi-tbm.ll
@@ -306,6 +306,27 @@
   ret i64 %1
 }
 
+define i32 @test_x86_pext_32_shifted_mask(i32 %x) nounwind readnone {
+; CHECK-LABEL: @test_x86_pext_32_shifted_mask(
+; CHECK-NEXT:    %1 = lshr i32 %x, 1
+; CHECK-NEXT:    %2 = and i32 %1, 3
+; CHECK-NEXT:    ret i32 %2
+;
+  %1 = tail call i32 @llvm.x86.bmi.pext.32(i32 %x, i32 6)
+  ret i32 %1
+}
+
+define i64 @test_x86_pext_64_shifted_mask(i64 %x) nounwind readnone {
+; CHECK-LABEL: @test_x86_pext_64_shifted_mask(
+; CHECK-NEXT:    %1 = lshr i64 %x, 1
+; CHECK-NEXT:    %2 = and i64 %1, 3
+; CHECK-NEXT:    ret i64 %2
+;
+  %1 = tail call i64 @llvm.x86.bmi.pext.64(i64 %x, i64 6)
+  ret i64 %1
+}
+
+
 define i32 @test_x86_pext_32_constant_fold() nounwind readnone {
 ; CHECK-LABEL: @test_x86_pext_32_constant_fold(
 ; CHECK-NEXT:    ret i32 30001
@@ -370,6 +391,27 @@
   ret i64 %1
 }
 
+define i32 @test_x86_pdep_32_shifted_mask(i32 %x) nounwind readnone {
+; CHECK-LABEL: @test_x86_pdep_32_shifted_mask(
+; CHECK-NEXT:    %1 = shl i32 %x, 2
+; CHECK-NEXT:    %2 = and i32 %1, 12
+; CHECK-NEXT:    ret i32 %2
+;
+  %1 = tail call i32 @llvm.x86.bmi.pdep.32(i32 %x, i32 12)
+  ret i32 %1
+}
+
+define i64 @test_x86_pdep_64_shifted_mask(i64 %x) nounwind readnone {
+; CHECK-LABEL: @test_x86_pdep_64_shifted_mask(
+; CHECK-NEXT:    %1 = shl i64 %x, 2
+; CHECK-NEXT:    %2 = and i64 %1, 12
+; CHECK-NEXT:    ret i64 %2
+;
+  %1 = tail call i64 @llvm.x86.bmi.pdep.64(i64 %x, i64 12)
+  ret i64 %1
+}
+
+
 define i32 @test_x86_pdep_32_constant_fold() nounwind readnone {
 ; CHECK-LABEL: @test_x86_pdep_32_constant_fold(
 ; CHECK-NEXT:    ret i32 807407616