Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4478,6 +4478,24 @@
                                Pred == ICmpInst::ICMP_EQ);
 }
 
+/// Try to simplify a select instruction when its condition operand is an
+/// integer equality comparison.
+static Value *simplifySelectWithICmpEq(Value *CmpLHS, Value *CmpRHS,
+                                       Value *TrueVal, Value *FalseVal,
+                                       const SimplifyQuery &Q,
+                                       unsigned MaxRecurse) {
+  if (simplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q,
+                             /* AllowRefinement */ false,
+                             MaxRecurse) == TrueVal)
+    return FalseVal;
+  if (simplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q,
+                             /* AllowRefinement */ true,
+                             MaxRecurse) == FalseVal)
+    return FalseVal;
+
+  return nullptr;
+}
+
 /// Try to simplify a select instruction when its condition operand is an
 /// integer comparison.
 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
@@ -4566,30 +4584,31 @@
   // the arms of the select. See if substituting this value into the arm and
   // simplifying the result yields the same value as the other arm.
   if (Pred == ICmpInst::ICMP_EQ) {
-    if (simplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q,
-                               /* AllowRefinement */ false,
-                               MaxRecurse) == TrueVal ||
-        simplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q,
-                               /* AllowRefinement */ false,
-                               MaxRecurse) == TrueVal)
-      return FalseVal;
-    if (simplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q,
-                               /* AllowRefinement */ true,
-                               MaxRecurse) == FalseVal ||
-        simplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q,
-                               /* AllowRefinement */ true,
-                               MaxRecurse) == FalseVal)
-      return FalseVal;
+    if (Value *V = simplifySelectWithICmpEq(CmpLHS, CmpRHS, TrueVal, FalseVal,
+                                            Q, MaxRecurse))
+      return V;
+    if (Value *V = simplifySelectWithICmpEq(CmpRHS, CmpLHS, TrueVal, FalseVal,
+                                            Q, MaxRecurse))
+      return V;
+
+    // select(X | Y == 0 ?  X : 0) --> 0 (commuted 2 ways)
+    Value *X;
+    Value *Y;
+    if (match(CmpLHS, m_Or(m_Value(X), m_Value(Y))) &&
+        match(CmpRHS, m_Zero())) {
+      // X | Y == 0 implies X == 0 and Y == 0.
+      if (Value *V = simplifySelectWithICmpEq(X, CmpRHS, TrueVal, FalseVal, Q,
+                                              MaxRecurse))
+        return V;
+      if (Value *V = simplifySelectWithICmpEq(Y, CmpRHS, TrueVal, FalseVal, Q,
+                                              MaxRecurse))
+        return V;
+    }
   }
 
   if (Pred == ICmpInst::Predicate::ICMP_EQ) {
     Value *X;
     Value *Y;
-    // select(X | Y == 0, X or Y, X | Y) -> X | Y
-    if (match(CondVal, m_ICmp(Pred, m_Specific(FalseVal), m_Zero())) &&
-        match(FalseVal, m_Or(m_Value(X), m_Value(Y))) &&
-        (TrueVal == X || TrueVal == Y))
-      return FalseVal;
     // select(X & Y == -1, X or Y, X & Y) -> X & Y
     if (match(CondVal, m_ICmp(Pred, m_Specific(FalseVal), m_AllOnes())) &&
         match(FalseVal, m_And(m_Value(X), m_Value(Y))) &&
Index: llvm/test/Transforms/InstCombine/select-ctlz-to-cttz.ll
===================================================================
--- llvm/test/Transforms/InstCombine/select-ctlz-to-cttz.ll
+++ llvm/test/Transforms/InstCombine/select-ctlz-to-cttz.ll
@@ -141,6 +141,7 @@
   ret i32 %cond
 }
 
+; TODO: https://alive2.llvm.org/ce/z/X6QjcB
 define i64 @select_clz_to_ctz_i64_wrong_xor(i64 %a) {
 ; CHECK-LABEL: @select_clz_to_ctz_i64_wrong_xor(
 ; CHECK-NEXT:    [[SUB:%.*]] = sub i64 0, [[A:%.*]]
Index: llvm/test/Transforms/InstSimplify/select-cmp-or.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/InstSimplify/select-cmp-or.ll
@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
+
+; TODO: https://alive2.llvm.org/ce/z/1ILbih
+define i32 @select_icmp_and_eq(i32 %a, i32 %b) {
+; CHECK-LABEL: @select_icmp_and_eq(
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[AND]], -1
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[TOBOOL]], i32 [[A]], i32 -1
+; CHECK-NEXT:    ret i32 [[COND]]
+;
+  %and = and i32 %a, %b
+  %tobool = icmp eq i32 %and, -1
+  %cond = select i1 %tobool, i32 %a, i32 -1
+  ret i32 %cond
+}
+
+; https://alive2.llvm.org/ce/z/hSyCuR
+define i32 @select_icmp_or_eq(i32 %a, i32 %b) {
+; CHECK-LABEL: @select_icmp_or_eq(
+; CHECK-NEXT:    ret i32 0
+;
+  %or = or i32 %a, %b
+  %tobool = icmp eq i32 %or, 0
+  %cond = select i1 %tobool, i32 %a, i32 0
+  ret i32 %cond
+}
+
+define i32 @select_icmp_or_eq_commuted(i32 %a0, i32 %b) {
+; CHECK-LABEL: @select_icmp_or_eq_commuted(
+; CHECK-NEXT:    ret i32 0
+;
+  %a = mul i32 %a0, 43         ; thwart complexity-based canonicalization
+  %or = or i32 %a, %b
+  %tobool = icmp eq i32 %or, 0
+  %cond = select i1 %tobool, i32 %b, i32 0
+  ret i32 %cond
+}
+
+; https://alive2.llvm.org/ce/z/S_pQek
+define <2 x i16> @select_icmp_or_eq_vec(<2 x i16> %a, <2 x i16> %b) {
+; CHECK-LABEL: @select_icmp_or_eq_vec(
+; CHECK-NEXT:    ret <2 x i16> zeroinitializer
+;
+  %or = or <2 x i16> %a, %b
+  %tobool = icmp eq <2 x i16> %or, <i16 0, i16 0>
+  %cond = select <2 x i1> %tobool, <2 x i16> %a, <2 x i16> zeroinitializer
+  ret <2 x i16> %cond
+}
+
+; The ne will be normalized to eq above
+define i32 @select_icmp_or_ne(i32 %a, i32 %b) {
+; CHECK-LABEL: @select_icmp_or_ne(
+; CHECK-NEXT:    ret i32 0
+;
+  %or = or i32 %a, %b
+  %tobool = icmp ne i32 %or, 0
+  %cond = select i1 %tobool, i32 0, i32 %a
+  ret i32 %cond
+}
Index: llvm/test/Transforms/InstSimplify/select_or_and.ll
===================================================================
--- llvm/test/Transforms/InstSimplify/select_or_and.ll
+++ llvm/test/Transforms/InstSimplify/select_or_and.ll
@@ -64,10 +64,7 @@
 ; select(Y | X == 0, Y | X, Y)
 define i32 @select_or_not_1(i32 %x, i32 %y) {
 ; CHECK-LABEL: @select_or_not_1(
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[Y:%.*]], [[X:%.*]]
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[OR]], 0
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[OR]], i32 [[Y]]
-; CHECK-NEXT:    ret i32 [[RET]]
+; CHECK-NEXT:    ret i32 [[Y:%.*]]
 ;
   %or = or i32 %y, %x
   %cmp = icmp eq i32 %or, 0
@@ -77,10 +74,7 @@
 ; select(Y | X != 0, Y, Y | X)
 define i32 @select_or_not_2(i32 %x, i32 %y) {
 ; CHECK-LABEL: @select_or_not_2(
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[Y:%.*]], [[X:%.*]]
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[OR]], 0
-; CHECK-NEXT:    [[RET:%.*]] = select i1 [[CMP]], i32 [[Y]], i32 [[OR]]
-; CHECK-NEXT:    ret i32 [[RET]]
+; CHECK-NEXT:    ret i32 [[Y:%.*]]
 ;
   %or = or i32 %y, %x
   %cmp = icmp ne i32 %or, 0