diff --git a/llvm/include/llvm/Analysis/ValueTracking.h b/llvm/include/llvm/Analysis/ValueTracking.h
--- a/llvm/include/llvm/Analysis/ValueTracking.h
+++ b/llvm/include/llvm/Analysis/ValueTracking.h
@@ -930,6 +930,13 @@
 /// impliesPoison returns true.
 bool impliesPoison(const Value *ValAssumedPoison, const Value *V);
 
+/// Return true if V is poison given that ValAssumedPoison is already poison.
+/// Poison generating flags or metadata are ignored in the process of implying.
+/// And the ignored instructions will be recorded in IgnoredInsts.
+bool impliesPoisonIgnoreFlagsOrMetadata(
+    Value *ValAssumedPoison, const Value *V,
+    SmallVectorImpl<Instruction *> &IgnoredInsts);
+
 /// Return true if this function can prove that V does not have undef bits
 /// and is never poison. If V is an aggregate value or vector, check whether
 /// all elements (except padding) are not undef or poison.
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -6743,8 +6743,9 @@
   return false;
 }
 
-static bool impliesPoison(const Value *ValAssumedPoison, const Value *V,
-                          unsigned Depth) {
+static bool
+impliesPoison(Value *ValAssumedPoison, const Value *V, unsigned Depth,
+              SmallVectorImpl<Instruction *> *IgnoredInsts = nullptr) {
   if (isGuaranteedNotToBePoison(ValAssumedPoison))
     return true;
 
@@ -6755,17 +6756,30 @@
   if (Depth >= MaxDepth)
     return false;
 
-  const auto *I = dyn_cast<Instruction>(ValAssumedPoison);
-  if (I && !canCreatePoison(cast<Operator>(I))) {
-    return all_of(I->operands(), [=](const Value *Op) {
-      return impliesPoison(Op, V, Depth + 1);
-    });
-  }
-  return false;
+  auto *I = dyn_cast<Instruction>(ValAssumedPoison);
+  if (!I || canCreatePoison(cast<Operator>(I),
+                            /*ConsiderFlagsAndMetadata*/ !IgnoredInsts))
+    return false;
+
+  for (Value *Op : I->operands())
+    if (!impliesPoison(Op, V, Depth + 1, IgnoredInsts))
+      return false;
+
+  if (IgnoredInsts && I->hasPoisonGeneratingFlagsOrMetadata())
+    IgnoredInsts->push_back(I);
+
+  return true;
 }
 
 bool llvm::impliesPoison(const Value *ValAssumedPoison, const Value *V) {
-  return ::impliesPoison(ValAssumedPoison, V, /* Depth */ 0);
+  return ::impliesPoison(const_cast<Value *>(ValAssumedPoison), V,
+                         /* Depth */ 0);
+}
+
+bool llvm::impliesPoisonIgnoreFlagsOrMetadata(
+    Value *ValAssumedPoison, const Value *V,
+    SmallVectorImpl<Instruction *> &IgnoredInsts) {
+  return ::impliesPoison(ValAssumedPoison, V, /* Depth */ 0, &IgnoredInsts);
 }
 
 static bool programUndefinedIfUndefOrPoison(const Value *V,
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2923,21 +2923,32 @@
   auto *Zero = ConstantInt::getFalse(SelType);
   Value *A, *B, *C, *D;
 
+  auto dropPoisonGeneratingFlagsAndMetadata =
+      [](ArrayRef<Instruction *> Insts) {
+        for (auto *I : Insts)
+          I->dropPoisonGeneratingFlagsAndMetadata();
+      };
   // Folding select to and/or i1 isn't poison safe in general. impliesPoison
   // checks whether folding it does not convert a well-defined value into
   // poison.
   if (match(TrueVal, m_One())) {
-    if (impliesPoison(FalseVal, CondVal)) {
-      // Change: A = select B, true, C --> A = or B, C
-      return BinaryOperator::CreateOr(CondVal, FalseVal);
-    }
-
     if (auto *LHS = dyn_cast<FCmpInst>(CondVal))
       if (auto *RHS = dyn_cast<FCmpInst>(FalseVal))
         if (Value *V = foldLogicOfFCmps(LHS, RHS, /*IsAnd*/ false,
                                         /*IsSelectLogical*/ true))
           return replaceInstUsesWith(SI, V);
 
+    // Some patterns can be matched by both of the above and following
+    // combinations. Because we need to drop poison generating
+    // flags and metadatas for the following combination, it has less priority
+    // than the above combination.
+    SmallVector<Instruction *> IgnoredInsts;
+    if (impliesPoisonIgnoreFlagsOrMetadata(FalseVal, CondVal, IgnoredInsts)) {
+      dropPoisonGeneratingFlagsAndMetadata(IgnoredInsts);
+      // Change: A = select B, true, C --> A = or B, C
+      return BinaryOperator::CreateOr(CondVal, FalseVal);
+    }
+
     // (A && B) || (C && B) --> (A || C) && B
     if (match(CondVal, m_LogicalAnd(m_Value(A), m_Value(B))) &&
         match(FalseVal, m_LogicalAnd(m_Value(C), m_Value(D))) &&
@@ -2968,17 +2979,23 @@
   }
 
   if (match(FalseVal, m_Zero())) {
-    if (impliesPoison(TrueVal, CondVal)) {
-      // Change: A = select B, C, false --> A = and B, C
-      return BinaryOperator::CreateAnd(CondVal, TrueVal);
-    }
-
     if (auto *LHS = dyn_cast<FCmpInst>(CondVal))
       if (auto *RHS = dyn_cast<FCmpInst>(TrueVal))
         if (Value *V = foldLogicOfFCmps(LHS, RHS, /*IsAnd*/ true,
                                         /*IsSelectLogical*/ true))
           return replaceInstUsesWith(SI, V);
 
+    // Some patterns can be matched by both of the above and following
+    // combinations. Because we need to drop poison generating
+    // flags and metadatas for the following combination, it has less priority
+    // than the above combination.
+    SmallVector<Instruction *> IgnoredInsts;
+    if (impliesPoisonIgnoreFlagsOrMetadata(TrueVal, CondVal, IgnoredInsts)) {
+      dropPoisonGeneratingFlagsAndMetadata(IgnoredInsts);
+      // Change: A = select B, C, false --> A = and B, C
+      return BinaryOperator::CreateAnd(CondVal, TrueVal);
+    }
+
     // (A || B) && (C || B) --> (A && C) || B
     if (match(CondVal, m_LogicalOr(m_Value(A), m_Value(B))) &&
         match(TrueVal, m_LogicalOr(m_Value(C), m_Value(D))) &&
diff --git a/llvm/test/Transforms/InstCombine/ispow2.ll b/llvm/test/Transforms/InstCombine/ispow2.ll
--- a/llvm/test/Transforms/InstCombine/ispow2.ll
+++ b/llvm/test/Transforms/InstCombine/ispow2.ll
@@ -282,7 +282,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i32 [[T0]], 3
 ; CHECK-NEXT:    [[NOTZERO:%.*]] = icmp ne i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[NOTZERO]], i1 [[CMP]], i1 false
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOTZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -314,7 +314,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i32 [[T0]], 2
 ; CHECK-NEXT:    [[NOTZERO:%.*]] = icmp ne i32 [[X]], 1
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[NOTZERO]], i1 [[CMP]], i1 false
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOTZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -346,7 +346,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[T0]], 2
 ; CHECK-NEXT:    [[NOTZERO:%.*]] = icmp ne i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[NOTZERO]], i1 [[CMP]], i1 false
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOTZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -378,7 +378,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i32 [[T0]], 2
 ; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP2]], i1 [[CMP]], i1 false
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[CMP2]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -493,7 +493,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[T0]], 2
 ; CHECK-NEXT:    [[ISZERO:%.*]] = icmp eq i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[ISZERO]], i1 true, i1 [[CMP]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[ISZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -525,7 +525,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[T0]], 1
 ; CHECK-NEXT:    [[ISZERO:%.*]] = icmp eq i32 [[X]], 1
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[ISZERO]], i1 true, i1 [[CMP]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[ISZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -557,7 +557,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[T0]], 1
 ; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP2]], i1 true, i1 [[CMP]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[CMP2]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -855,7 +855,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[T0]], 3
 ; CHECK-NEXT:    [[ISZERO:%.*]] = icmp eq i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[ISZERO]], i1 true, i1 [[CMP]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[ISZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -914,7 +914,11 @@
 
 define i1 @is_pow2or0_ctpop_wrong_pred2_logical(i32 %x) {
 ; CHECK-LABEL: @is_pow2or0_ctpop_wrong_pred2_logical(
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[T0]], 1
+; CHECK-NEXT:    [[ISZERO:%.*]] = icmp ne i32 [[X]], 0
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[ISZERO]], [[CMP]]
+; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
   %cmp = icmp ne i32 %t0, 1
@@ -1058,7 +1062,7 @@
 ; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[T0]], 5
 ; CHECK-NEXT:    [[NOTZERO:%.*]] = icmp ne i32 [[X]], 0
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[NOTZERO]], i1 [[CMP]], i1 false
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOTZERO]], [[CMP]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
@@ -1117,7 +1121,11 @@
 
 define i1 @isnot_pow2nor0_ctpop_wrong_pred2_logical(i32 %x) {
 ; CHECK-LABEL: @isnot_pow2nor0_ctpop_wrong_pred2_logical(
-; CHECK-NEXT:    ret i1 false
+; CHECK-NEXT:    [[T0:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[T0]], 1
+; CHECK-NEXT:    [[NOTZERO:%.*]] = icmp eq i32 [[X]], 0
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOTZERO]], [[CMP]]
+; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t0 = tail call i32 @llvm.ctpop.i32(i32 %x)
   %cmp = icmp eq i32 %t0, 1
diff --git a/llvm/test/Transforms/InstCombine/prevent-cmp-merge.ll b/llvm/test/Transforms/InstCombine/prevent-cmp-merge.ll
--- a/llvm/test/Transforms/InstCombine/prevent-cmp-merge.ll
+++ b/llvm/test/Transforms/InstCombine/prevent-cmp-merge.ll
@@ -71,10 +71,10 @@
 
 define zeroext i1 @test3_logical(i32 %lhs, i32 %rhs) {
 ; CHECK-LABEL: @test3_logical(
-; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[LHS:%.*]], [[RHS:%.*]]
+; CHECK-NEXT:    [[SUB:%.*]] = sub i32 [[LHS:%.*]], [[RHS:%.*]]
 ; CHECK-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[LHS]], [[RHS]]
 ; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[SUB]], 31
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i1 true, i1 [[CMP2]]
+; CHECK-NEXT:    [[SEL:%.*]] = or i1 [[CMP1]], [[CMP2]]
 ; CHECK-NEXT:    ret i1 [[SEL]]
 ;