Index: lib/Transforms/Utils/SimplifyIndVar.cpp
===================================================================
--- lib/Transforms/Utils/SimplifyIndVar.cpp
+++ lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -521,9 +521,36 @@
 }
 
 /// Annotate BO with nsw / nuw if it provably does not signed-overflow /
-/// unsigned-overflow.  Returns true if anything changed, false otherwise.
+/// unsigned-overflow.  Also check for shifts that can be marked as exact.
+/// Returns true if anything changed, false otherwise.
 bool SimplifyIndvar::strengthenOverflowingOperation(BinaryOperator *BO,
                                                     Value *IVOperand) {
+  // match (X << IVOperand) >> C, marking the AShr as exact using the
+  // information from the IV's range
+  if(BO->getOpcode() == Instruction::Shl) {
+    bool Changed = false;
+    for(auto* user : BO->users()) {
+      BinaryOperator* AShr = dyn_cast<BinaryOperator>(user);
+      if(!AShr || AShr->getOpcode() != Instruction::AShr ||
+          AShr->getOperand(0) != BO || AShr->isExact())
+        continue;
+
+      ConstantRange IVRange = SE->getUnsignedRange(SE->getSCEV(IVOperand));
+
+      Value* ShlOp1 = BO->getOperand(0);
+      if(ShlOp1 == IVOperand || !BO->getType()->isIntegerTy() ||
+          IVRange.getUpper().uge(BO->getType()->getPrimitiveSizeInBits()))
+        continue;
+
+      ConstantInt* AShrOp2 = dyn_cast<ConstantInt>(AShr->getOperand(1));
+      if(!AShrOp2 || IVRange.getLower().ult(AShrOp2->getValue()))
+        continue;
+
+      AShr->setIsExact(true);
+      Changed = true;
+    }
+    return Changed;
+  }
 
   // Fastpath: we don't have any work to do if `BO` is `nuw` and `nsw`.
   if (BO->hasNoUnsignedWrap() && BO->hasNoSignedWrap())
Index: test/Transforms/IndVarSimplify/strengthen-overflow.ll
===================================================================
--- test/Transforms/IndVarSimplify/strengthen-overflow.ll
+++ test/Transforms/IndVarSimplify/strengthen-overflow.ll
@@ -104,5 +104,37 @@
   ret i32 42
 }
 
+define hidden void @test.shl() {
+; CHECK-LABEL: @test.shl
+entry:
+  br label %for.body
+
+for.body:
+; CHECK-LABEL: for.body
+  %k.021 = phi i32 [ 1, %entry ], [ %inc, %for.body ]
+  %shl = shl i32 1, %k.021
+  %shr = ashr i32 %shl, 1
+; CHECK: %shr = ashr exact i32 %shl, 1
+  %div = sdiv i32 %shr, 2
+  %add = add nsw i32 %div, %shr
+  %arrayidx = getelementptr inbounds [16 x i32], [16 x i32]* @Data, i32 0, i32 %add
+  %arrayidx1 = getelementptr inbounds [16 x i32], [16 x i32]* @Data, i32 0, i32 %div
+  %0 = load i32, i32* %arrayidx, align 4
+  %1 = load i32, i32* %arrayidx1, align 4
+  %sub = sub nsw i32 %1, %0
+  store i32 %sub, i32* %arrayidx, align 4
+  %2 = load i32, i32* %arrayidx1, align 4
+  %add4 = add nsw i32 %2, %0
+  store i32 %add4, i32* %arrayidx1, align 4
+  %inc = add nuw nsw i32 %k.021, 1
+  %exitcond = icmp eq i32 %inc, 9
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+@Data = hidden local_unnamed_addr global [16 x i32] zeroinitializer, align 4
+
 !0 = !{i32 0, i32 2}
 !1 = !{i32 0, i32 42}