Index: lib/Analysis/InstructionSimplify.cpp
===================================================================
--- lib/Analysis/InstructionSimplify.cpp
+++ lib/Analysis/InstructionSimplify.cpp
@@ -69,6 +69,36 @@
 static Value *SimplifyGEPInst(Type *, ArrayRef<Value *>, const SimplifyQuery &,
                               unsigned);
 
+/// We want to turn:
+///   (select (icmp sgt x, C), lshr (X, Y), ashr (X, Y)); C >= -1
+///   (select (icmp slt x, C), ashr (X, Y), lshr (X, Y)); C >= 0
+/// into:
+///   ashr (X, Y)
+/// if both of the shifts either have or have no exact; or only
+/// lshr is exact.
+static Value *foldSelectICmpLshrAshr(const ICmpInst::Predicate Pred,
+                                     const Value *CmpLHS, const Value *CmpRHS,
+                                     Value *TrueVal, Value *FalseVal) {
+  Value *X, *Y;
+  const APInt *C;
+  if ((Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_APInt(C)) && C->sge(-1)) ||
+      (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, m_APInt(C)) && C->sge(0))) {
+    if (Pred == ICmpInst::ICMP_SLT)
+      std::swap(TrueVal, FalseVal);
+
+    if (match(TrueVal, m_LShr(m_Value(X), m_Value(Y))) &&
+        match(FalseVal, m_AShr(m_Specific(X), m_Specific(Y))) &&
+        match(CmpLHS, m_Specific(X))) {
+      if (!cast<BinaryOperator>(TrueVal)->isExact() &&
+          cast<BinaryOperator>(FalseVal)->isExact())
+        return nullptr;
+      return FalseVal;
+    }
+  }
+
+  return nullptr;
+}
+
 static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal,
                                      Value *FalseVal) {
   BinaryOperator::BinaryOps BinOpCode;
@@ -3761,6 +3791,10 @@
       return TrueVal;
   }
 
+  if (Value *V =
+          foldSelectICmpLshrAshr(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal))
+    return V;
+
   return nullptr;
 }
 
Index: lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -532,6 +532,39 @@
 }
 
 /// We want to turn:
+///   (select (icmp sgt x, C), lshr (X, Y), ashr (X, Y)); C>= -1
+///   (select (icmp slt x, C), ashr (X, Y), lshr (X, Y)); C >= 0
+/// into:
+///   ashr (X, Y)
+/// iff only ashr is exact.
+static Value *foldSelectICmpLshrAshr(const ICmpInst *IC, Value *TrueVal,
+                                     Value *FalseVal,
+                                     InstCombiner::BuilderTy &Builder) {
+  ICmpInst::Predicate Pred = IC->getPredicate();
+  Value *CmpLHS = IC->getOperand(0);
+  Value *CmpRHS = IC->getOperand(1);
+
+  Value *X, *Y;
+  const APInt *C;
+  if ((Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_APInt(C)) && C->sge(-1)) ||
+      (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, m_APInt(C)) && C->sge(0))) {
+    if (Pred == ICmpInst::ICMP_SLT)
+      std::swap(TrueVal, FalseVal);
+
+    if (match(TrueVal, m_LShr(m_Value(X), m_Value(Y))) &&
+        match(FalseVal, m_AShr(m_Specific(X), m_Specific(Y))) &&
+        match(CmpLHS, m_Specific(X)) &&
+        (!cast<BinaryOperator>(TrueVal)->isExact() &&
+         cast<BinaryOperator>(FalseVal)->isExact())) {
+      cast<BinaryOperator>(FalseVal)->setIsExact(false);
+      return FalseVal;
+    }
+  }
+
+  return nullptr;
+}
+
+/// We want to turn:
 ///   (select (icmp eq (and X, C1), 0), Y, (or Y, C2))
 /// into:
 ///   (or (shl (and X, C1), C3), Y)
@@ -1112,6 +1145,9 @@
   if (Value *V = foldSelectICmpAndOr(ICI, TrueVal, FalseVal, Builder))
     return replaceInstUsesWith(SI, V);
 
+  if (Value *V = foldSelectICmpLshrAshr(ICI, TrueVal, FalseVal, Builder))
+    return replaceInstUsesWith(SI, V);
+
   if (Value *V = foldSelectCttzCtlz(ICI, TrueVal, FalseVal, Builder))
     return replaceInstUsesWith(SI, V);
 
Index: test/Transforms/InstCombine/ashr-lshr.ll
===================================================================
--- test/Transforms/InstCombine/ashr-lshr.ll
+++ test/Transforms/InstCombine/ashr-lshr.ll
@@ -0,0 +1,347 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+define i32 @ashr_lshr(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, -1
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr2(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, 5
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define <2 x i32> @ashr_lshr_vec(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_vec(
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
+;
+  %cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr exact <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %l, <2 x i32> %r
+  ret <2 x i32> %ret
+}
+
+define i32 @ashr_lshr_cst(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_cst(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], 8
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp slt i32 %x, 1
+  %l = lshr i32 %x, 8
+  %r = ashr exact i32 %x, 8
+  %ret = select i1 %cmp, i32 %r, i32 %l
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_cst2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_cst2(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], 8
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, -1
+  %l = lshr i32 %x, 8
+  %r = ashr exact i32 %x, 8
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_inv(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_inv(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp slt i32 %x, 1
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %r, i32 %l
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_inv2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_inv2(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp slt i32 %x, 7
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %r, i32 %l
+  ret i32 %ret
+}
+
+define <2 x i32> @ashr_lshr_inv_vec(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_inv_vec(
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
+;
+  %cmp = icmp slt <2 x i32> %x, <i32 1, i32 1>
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr exact <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %r, <2 x i32> %l
+  ret <2 x i32> %ret
+}
+
+; Negative tests
+
+define i32 @ashr_lshr_wrong_cst(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_wrong_cst(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -2
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sgt i32 %x, -2
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_wrong_cst2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_wrong_cst2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[R]], i32 [[L]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp slt i32 %x, -1
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %r, i32 %l
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_wrong_cond(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_wrong_cond(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -2
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %x, -1
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_shift_wrong_pred(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: @ashr_lshr_shift_wrong_pred(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sle i32 %x, 0
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_shift_wrong_pred2(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: @ashr_lshr_shift_wrong_pred2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[Z:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %z, 0
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_wrong_operands(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_wrong_operands(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[R]], i32 [[L]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %x, 0
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %r, i32 %l
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_no_ashr(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_no_ashr(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = xor i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %x, 0
+  %l = lshr i32 %x, %y
+  %r = xor i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_shift_amt_mismatch(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: @ashr_lshr_shift_amt_mismatch(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Z:%.*]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %x, 0
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %z
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_shift_base_mismatch(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: @ashr_lshr_shift_base_mismatch(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[Z:%.*]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %x, 0
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %z, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_no_lshr(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_no_lshr(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = add i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sge i32 %x, 0
+  %l = add i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define <2 x i32> @ashr_lshr_vec_wrong_pred(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_vec_wrong_pred(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 1, i32 1>
+; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[L]], <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %cmp = icmp sle <2 x i32> %x, zeroinitializer
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %l, <2 x i32> %r
+  ret <2 x i32> %ret
+}
+
+define <2 x i32> @ashr_lshr_inv_vec_wrong_pred(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_inv_vec_wrong_pred(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
+; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[R]], <2 x i32> [[L]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %cmp = icmp sge <2 x i32> %x, zeroinitializer
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %r, <2 x i32> %l
+  ret <2 x i32> %ret
+}
+
+define i32 @ashr_lshr_no_exact(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_no_exact(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, -1
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+
+define i32 @ashr_lshr_exact_both(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_exact_both(
+; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, -1
+  %l = lshr exact i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_exact_mismatch2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_exact_mismatch2(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, -1
+  %l = lshr exact i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define <2 x i32> @ashr_lshr_vec_undef(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_vec_undef(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 undef, i32 -1>
+; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[L]], <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %cmp = icmp sgt <2 x i32> %x, <i32 undef, i32 -1>
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr exact <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %l, <2 x i32> %r
+  ret <2 x i32> %ret
+}
+
+define <2 x i32> @ashr_lshr_vec_undef2(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_vec_undef2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 1, i32 undef>
+; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[R]], <2 x i32> [[L]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %cmp = icmp slt <2 x i32> %x, <i32 1, i32 undef>
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr exact <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %r, <2 x i32> %l
+  ret <2 x i32> %ret
+}
Index: test/Transforms/InstSimplify/ashr-lshr.ll
===================================================================
--- test/Transforms/InstSimplify/ashr-lshr.ll
+++ test/Transforms/InstSimplify/ashr-lshr.ll
@@ -3,11 +3,8 @@
 
 define i32 @ashr_lshr(i32 %x, i32 %y) {
 ; CHECK-LABEL: @ashr_lshr(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
-; CHECK-NEXT:    ret i32 [[RET]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
 ;
   %cmp = icmp sgt i32 %x, -1
   %l = lshr i32 %x, %y
@@ -16,13 +13,22 @@
   ret i32 %ret
 }
 
-define i32 @ashr_lshr_exact(i32 %x, i32 %y) {
-; CHECK-LABEL: @ashr_lshr_exact(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT:    [[L:%.*]] = lshr exact i32 [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
-; CHECK-NEXT:    ret i32 [[RET]]
+define i32 @ashr_lshr2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr2(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp sgt i32 %x, 8
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}
+
+define i32 @ashr_lshr_exact_both(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_exact_both(
+; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
 ;
   %cmp = icmp sgt i32 %x, -1
   %l = lshr exact i32 %x, %y
@@ -31,16 +37,13 @@
   ret i32 %ret
 }
 
-define i32 @ashr_lshr2(i32 %x, i32 %y) {
-; CHECK-LABEL: @ashr_lshr2(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
-; CHECK-NEXT:    ret i32 [[RET]]
+define i32 @ashr_lshr_exact_lshr_only(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_exact_lshr_only(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
 ;
   %cmp = icmp sgt i32 %x, -1
-  %l = lshr i32 %x, %y
+  %l = lshr exact i32 %x, %y
   %r = ashr i32 %x, %y
   %ret = select i1 %cmp, i32 %l, i32 %r
   ret i32 %ret
@@ -48,11 +51,8 @@
 
 define <2 x i32> @ashr_lshr_vec(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @ashr_lshr_vec(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[L]], <2 x i32> [[R]]
-; CHECK-NEXT:    ret <2 x i32> [[RET]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
 ;
   %cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
   %l = lshr <2 x i32> %x, %y
@@ -63,41 +63,32 @@
 
 define <2 x i32> @ashr_lshr_vec2(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @ashr_lshr_vec2(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 undef, i32 -1>
-; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[L]], <2 x i32> [[R]]
-; CHECK-NEXT:    ret <2 x i32> [[RET]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
 ;
-  %cmp = icmp sgt <2 x i32> %x, <i32 undef, i32 -1>
-  %l = lshr <2 x i32> %x, %y
-  %r = ashr <2 x i32> %x, %y
+  %cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
+  %l = lshr exact <2 x i32> %x, %y
+  %r = ashr exact <2 x i32> %x, %y
   %ret = select <2 x i1> %cmp, <2 x i32> %l, <2 x i32> %r
   ret <2 x i32> %ret
 }
 
 define <2 x i32> @ashr_lshr_vec3(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @ashr_lshr_vec3(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 1, i32 undef>
-; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[R]], <2 x i32> [[L]]
-; CHECK-NEXT:    ret <2 x i32> [[RET]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
 ;
-  %cmp = icmp slt <2 x i32> %x, <i32 1, i32 undef>
-  %l = lshr <2 x i32> %x, %y
+  %cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
+  %l = lshr exact <2 x i32> %x, %y
   %r = ashr <2 x i32> %x, %y
-  %ret = select <2 x i1> %cmp, <2 x i32> %r, <2 x i32> %l
+  %ret = select <2 x i1> %cmp, <2 x i32> %l, <2 x i32> %r
   ret <2 x i32> %ret
 }
 
 define i32 @ashr_lshr_inv(i32 %x, i32 %y) {
 ; CHECK-LABEL: @ashr_lshr_inv(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X:%.*]], 1
-; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[R]], i32 [[L]]
-; CHECK-NEXT:    ret i32 [[RET]]
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
 ;
   %cmp = icmp slt i32 %x, 1
   %l = lshr i32 %x, %y
@@ -106,13 +97,22 @@
   ret i32 %ret
 }
 
+define i32 @ashr_lshr_inv2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_inv2(
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %cmp = icmp slt i32 %x, 5
+  %l = lshr i32 %x, %y
+  %r = ashr i32 %x, %y
+  %ret = select i1 %cmp, i32 %r, i32 %l
+  ret i32 %ret
+}
+
 define <2 x i32> @ashr_lshr_inv_vec(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @ashr_lshr_inv_vec(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 1, i32 1>
-; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[R]], <2 x i32> [[L]]
-; CHECK-NEXT:    ret <2 x i32> [[RET]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i32> [[R]]
 ;
   %cmp = icmp slt <2 x i32> %x, <i32 1, i32 1>
   %l = lshr <2 x i32> %x, %y
@@ -121,38 +121,38 @@
   ret <2 x i32> %ret
 }
 
-define i32 @ashr_lshr_exact_mismatch(i32 %x, i32 %y) {
-; CHECK-LABEL: @ashr_lshr_exact_mismatch(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; Negative tests
+
+define i32 @ashr_lshr_wrong_cst(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_wrong_cst(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -2
 ; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
 ; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X]], [[Y]]
 ; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
 ; CHECK-NEXT:    ret i32 [[RET]]
 ;
-  %cmp = icmp sgt i32 %x, -1
+  %cmp = icmp sgt i32 %x, -2
   %l = lshr i32 %x, %y
   %r = ashr exact i32 %x, %y
   %ret = select i1 %cmp, i32 %l, i32 %r
   ret i32 %ret
 }
 
-define i32 @ashr_lshr_exact_mismatch2(i32 %x, i32 %y) {
-; CHECK-LABEL: @ashr_lshr_exact_mismatch2(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+define i32 @ashr_lshr_wrong_cst2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_wrong_cst2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X:%.*]], -1
 ; CHECK-NEXT:    [[L:%.*]] = lshr exact i32 [[X]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[R]], i32 [[L]]
 ; CHECK-NEXT:    ret i32 [[RET]]
 ;
-  %cmp = icmp sgt i32 %x, -1
+  %cmp = icmp slt i32 %x, -1
   %l = lshr exact i32 %x, %y
-  %r = ashr i32 %x, %y
-  %ret = select i1 %cmp, i32 %l, i32 %r
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %r, i32 %l
   ret i32 %ret
 }
 
-; Negative tests
-
 define i32 @ashr_lshr_wrong(i32 %x, i32 %y) {
 ; CHECK-LABEL: @ashr_lshr_wrong(
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sge i32 [[X:%.*]], -1
@@ -302,3 +302,48 @@
   %ret = select <2 x i1> %cmp, <2 x i32> %r, <2 x i32> %l
   ret <2 x i32> %ret
 }
+
+define <2 x i32> @ashr_lshr_undef2(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_undef2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 undef, i32 -1>
+; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[L]], <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %cmp = icmp sgt <2 x i32> %x, <i32 undef, i32 -1>
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %l, <2 x i32> %r
+  ret <2 x i32> %ret
+}
+
+define <2 x i32> @ashr_lshr_undef3(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @ashr_lshr_undef3(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 1, i32 undef>
+; CHECK-NEXT:    [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[R]], <2 x i32> [[L]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %cmp = icmp slt <2 x i32> %x, <i32 1, i32 undef>
+  %l = lshr <2 x i32> %x, %y
+  %r = ashr <2 x i32> %x, %y
+  %ret = select <2 x i1> %cmp, <2 x i32> %r, <2 x i32> %l
+  ret <2 x i32> %ret
+}
+
+define i32 @ashr_lshr_exact_ashr_only(i32 %x, i32 %y) {
+; CHECK-LABEL: @ashr_lshr_exact_ashr_only(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = ashr exact i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %cmp = icmp sgt i32 %x, -1
+  %l = lshr i32 %x, %y
+  %r = ashr exact i32 %x, %y
+  %ret = select i1 %cmp, i32 %l, i32 %r
+  ret i32 %ret
+}