Index: lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2008,43 +2008,42 @@
     return nullptr;
 
   bool IsAShr = Shr->getOpcode() == Instruction::AShr;
-  if (!Cmp.isEquality()) {
-    // If we have an unsigned comparison and an ashr, we can't simplify this.
-    // Similarly for signed comparisons with lshr.
-    if (Cmp.isSigned() != IsAShr)
-      return nullptr;
-
-    // Otherwise, all lshr and most exact ashr's are equivalent to a udiv/sdiv
-    // by a power of 2.  Since we already have logic to simplify these,
-    // transform to div and then simplify the resultant comparison.
-    if (IsAShr && (!Shr->isExact() || ShAmtVal == TypeBits - 1))
-      return nullptr;
-
-    // Revisit the shift (to delete it).
-    Worklist.Add(Shr);
-
-    Constant *DivCst = ConstantInt::get(
-        Shr->getType(), APInt::getOneBitSet(TypeBits, ShAmtVal));
-
-    Value *Tmp = IsAShr ? Builder.CreateSDiv(X, DivCst, "", Shr->isExact())
-                        : Builder.CreateUDiv(X, DivCst, "", Shr->isExact());
-
-    Cmp.setOperand(0, Tmp);
-
-    // If the builder folded the binop, just return it.
-    BinaryOperator *TheDiv = dyn_cast<BinaryOperator>(Tmp);
-    if (!TheDiv)
-      return &Cmp;
-
-    // Otherwise, fold this div/compare.
-    assert(TheDiv->getOpcode() == Instruction::SDiv ||
-           TheDiv->getOpcode() == Instruction::UDiv);
-
-    Instruction *Res = foldICmpDivConstant(Cmp, TheDiv, C);
-    assert(Res && "This div/cst should have folded!");
-    return Res;
+  bool IsExact = Shr->isExact();
+  if (IsAShr) {
+    if (Pred == CmpInst::ICMP_SLT || (Pred == CmpInst::ICMP_SGT && IsExact)) {
+      // icmp slt (ashr X, ShAmtC), C --> icmp slt X, (C << ShAmtC)
+      // icmp sgt (ashr exact X, ShAmtC), C --> icmp sgt X, (C << ShAmtC)
+      APInt ShiftedC = C.shl(ShAmtVal);
+      assert(ShiftedC.ashr(ShAmtVal) == C && "Missed simplify");
+      return new ICmpInst(Pred, X, ConstantInt::get(Shr->getType(), ShiftedC));
+    }
+    if (Pred == CmpInst::ICMP_SGT) {
+      // icmp sgt (ashr X, ShAmtC), C --> icmp sgt X, ((C + 1) << ShAmtC) - 1
+      APInt ShiftedC = (C + 1).shl(ShAmtVal) - 1;
+      assert(!C.isMaxSignedValue() && "Missed simplify");
+      assert(!(C + 1).shl(ShAmtVal).isMinSignedValue() && "Missed simplify");
+      assert((ShiftedC + 1).ashr(ShAmtVal) == (C + 1) && "Missed simplify");
+      return new ICmpInst(Pred, X, ConstantInt::get(Shr->getType(), ShiftedC));
+    }
+  } else {
+    if (Pred == CmpInst::ICMP_ULT || (Pred == CmpInst::ICMP_UGT && IsExact)) {
+      // icmp ult (lshr X, ShAmtC), C --> icmp ult X, (C << ShAmtC)
+      // icmp ugt (lshr exact X, ShAmtC), C --> icmp ugt X, (C << ShAmtC)
+      APInt ShiftedC = C.shl(ShAmtVal);
+      assert(ShiftedC.lshr(ShAmtVal) == C && "Missed simplify");
+      return new ICmpInst(Pred, X, ConstantInt::get(Shr->getType(), ShiftedC));
+    }
+    if (Pred == CmpInst::ICMP_UGT) {
+      // icmp ugt (lshr X, ShAmtC), C --> icmp ugt X, ((C + 1) << ShAmtC) - 1
+      APInt ShiftedC = (C + 1).shl(ShAmtVal) - 1;
+      assert((ShiftedC + 1).lshr(ShAmtVal) == (C + 1) && "Missed simplify");
+      return new ICmpInst(Pred, X, ConstantInt::get(Shr->getType(), ShiftedC));
+    }
   }
 
+  if (!Cmp.isEquality())
+    return nullptr;
+
   // Handle equality comparisons of shift-by-constant.
 
   // If the comparison constant changes with the shift, the comparison cannot
Index: test/Transforms/InstCombine/icmp-shr-lt-gt.ll
===================================================================
--- test/Transforms/InstCombine/icmp-shr-lt-gt.ll
+++ test/Transforms/InstCombine/icmp-shr-lt-gt.ll
@@ -888,8 +888,7 @@
 
 define i1 @ashrsgt_01_00(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_01_00(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], 0
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, 1
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -899,8 +898,7 @@
 
 define i1 @ashrsgt_01_01(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_01_01(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], 1
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, 3
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -910,8 +908,7 @@
 
 define i1 @ashrsgt_01_02(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_01_02(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], 2
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, 5
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1002,8 +999,7 @@
 
 define i1 @ashrsgt_01_12(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_01_12(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], -4
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, -7
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1013,8 +1009,7 @@
 
 define i1 @ashrsgt_01_13(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_01_13(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], -3
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, -5
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1024,8 +1019,7 @@
 
 define i1 @ashrsgt_01_14(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_01_14(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], -2
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, -3
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1045,8 +1039,7 @@
 
 define i1 @ashrsgt_02_00(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_02_00(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 2
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], 0
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, 3
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 2
@@ -1173,8 +1166,7 @@
 
 define i1 @ashrsgt_02_14(i4 %x) {
 ; CHECK-LABEL: @ashrsgt_02_14(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 2
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 [[S]], -2
+; CHECK-NEXT:    [[C:%.*]] = icmp sgt i4 %x, -5
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 2
@@ -1349,8 +1341,7 @@
 
 define i1 @ashrslt_01_01(i4 %x) {
 ; CHECK-LABEL: @ashrslt_01_01(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], 1
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, 2
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1360,8 +1351,7 @@
 
 define i1 @ashrslt_01_02(i4 %x) {
 ; CHECK-LABEL: @ashrslt_01_02(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], 2
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, 4
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1371,8 +1361,7 @@
 
 define i1 @ashrslt_01_03(i4 %x) {
 ; CHECK-LABEL: @ashrslt_01_03(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], 3
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, 6
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1463,8 +1452,7 @@
 
 define i1 @ashrslt_01_13(i4 %x) {
 ; CHECK-LABEL: @ashrslt_01_13(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], -3
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, -6
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1474,8 +1462,7 @@
 
 define i1 @ashrslt_01_14(i4 %x) {
 ; CHECK-LABEL: @ashrslt_01_14(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], -2
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, -4
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1485,8 +1472,7 @@
 
 define i1 @ashrslt_01_15(i4 %x) {
 ; CHECK-LABEL: @ashrslt_01_15(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 1
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], -1
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, -2
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 1
@@ -1506,8 +1492,7 @@
 
 define i1 @ashrslt_02_01(i4 %x) {
 ; CHECK-LABEL: @ashrslt_02_01(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 2
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], 1
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, 4
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 2
@@ -1634,8 +1619,7 @@
 
 define i1 @ashrslt_02_15(i4 %x) {
 ; CHECK-LABEL: @ashrslt_02_15(
-; CHECK-NEXT:    [[S:%.*]] = ashr i4 %x, 2
-; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 [[S]], -1
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i4 %x, -4
 ; CHECK-NEXT:    ret i1 [[C]]
 ;
   %s = ashr i4 %x, 2