Index: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2696,5 +2696,33 @@
     return SelectInst::Create(Cmp, Builder.CreateNeg(A), A);
   }
 
+  // Perform canonicalization of the following min/max patterns:
+  //
+  //  %Xor = xor i32 %V, -1
+  //  %Cmp = icmp sgt[slt/ugt/ult] i32 %Xor, C
+  //  %Op0 = select i1 %Cmp, i32 %Xor, i32 C
+  //  %res = xor i32 %Op0, -1
+  // =>
+  //  %Cmp = icmp slt[sgt/ult/ugt] i32 %V, NewC
+  //  %res = select i1 %Cmp, i32 %V, i32 NewC
+  //
+  // where NewC = -1 xor C.
+  {
+    const Value *LHS, *RHS;
+    SelectPatternFlavor SPF = matchSelectPattern(Op0, LHS, RHS).Flavor;
+    if (SelectPatternResult::isMinOrMax(SPF) && match(Op1, m_AllOnes())) {
+      const APInt *C;
+      Value *V;
+      if (match(LHS, m_Xor(m_Value(V), m_AllOnes())) &&
+          match(RHS, m_APInt(C))) {
+        APInt FlippedC = APInt::getAllOnesValue(C->getBitWidth());
+        FlippedC ^= *C;
+        Constant *NewC = ConstantInt::get(V->getType(), FlippedC);
+        Value *Cmp = Builder.CreateICmp(getInverseMinMaxPred(SPF), V, NewC);
+        return SelectInst::Create(Cmp, V, NewC);
+      }
+    }
+  }
+
   return Changed ? &I : nullptr;
 }
Index: test/Transforms/InstCombine/xor.ll
===================================================================
--- test/Transforms/InstCombine/xor.ll
+++ test/Transforms/InstCombine/xor.ll
@@ -575,3 +575,85 @@
   %xor = xor i32 %and, %B
   ret i32 %xor
 }
+
+; The following 5 tests are related to the canonicalization:
+; https://rise4fun.com/Alive/8jH
+
+define i32 @test39(i32 %x) {
+; CHECK-LABEL: @test39(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 255
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 255
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+  %1 = xor i32 %x, -1
+  %2 = icmp sgt i32 %1, -256
+  %3 = select i1 %2, i32 %1, i32 -256
+  %res = xor i32 %3, -1
+  ret i32 %res
+}
+
+define i32 @test40(i32 %x) {
+; CHECK-LABEL: @test40(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i32 [[X:%.*]], 255
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 255
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+  %1 = xor i32 %x, -1
+  %2 = icmp slt i32 %1, -256
+  %3 = select i1 %2, i32 %1, i32 -256
+  %res = xor i32 %3, -1
+  ret i32 %res
+}
+
+define i32 @test41(i32 %x) {
+; CHECK-LABEL: @test41(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[X:%.*]], 255
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 255
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+  %1 = xor i32 %x, -1
+  %2 = icmp ugt i32 %1, -256
+  %3 = select i1 %2, i32 %1, i32 -256
+  %res = xor i32 %3, -1
+  ret i32 %res
+}
+
+define i32 @test42(i32 %x) {
+; CHECK-LABEL: @test42(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ugt i32 [[X:%.*]], 255
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 255
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+  %1 = xor i32 %x, -1
+  %2 = icmp ult i32 %1, -256
+  %3 = select i1 %2, i32 %1, i32 -256
+  %res = xor i32 %3, -1
+  ret i32 %res
+}
+
+define i8 @test43(i8 %x) {
+; CHECK-LABEL: @test43(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ugt i8 [[X:%.*]], 85
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[TMP1]], i8 [[X]], i8 85
+; CHECK-NEXT:    ret i8 [[RES]]
+;
+  %1 = xor i8 %x, -1
+  %2 = icmp ult i8 %1, 170
+  %3 = select i1 %2, i8 %1, i8 170
+  %res = xor i8 %3, -1
+  ret i8 %res
+}
+
+; Check that we work with splat vectors also.
+define <4 x i32> @test44(<4 x i32> %x) {
+; CHECK-LABEL: @test44(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp slt <4 x i32> [[X:%.*]], <i32 255, i32 255, i32 255, i32 255>
+; CHECK-NEXT:    [[TMP2:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> [[X]], <4 x i32> <i32 255, i32 255, i32 255, i32 255>
+; CHECK-NEXT:    ret <4 x i32> [[TMP2]]
+;
+  %1 = xor <4 x i32> %x, <i32 -1, i32 -1, i32 -1, i32 -1>
+  %2 = icmp sgt <4 x i32> %1, <i32 -256, i32 -256, i32 -256, i32 -256>
+  %3 = select <4 x i1> %2, <4 x i32> %1, <4 x i32> <i32 -256, i32 -256, i32 -256, i32 -256>
+  %4 = xor <4 x i32> %3, <i32 -1, i32 -1, i32 -1, i32 -1>
+  ret <4 x i32> %4
+}