Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4503,9 +4503,22 @@
     if (match(TrueVal, m_One()) && match(FalseVal, m_ZeroInt()))
       return Cond;
 
-    // (X || Y) && (X || !Y) --> X (commuted 8 ways)
     Value *X, *Y;
+
+    if (match(TrueVal, m_ZeroInt())) {
+      // !(X || Y) && X --> false (commuted 2 ways)
+      if (match(Cond, m_LogicalOr(m_Value(X), m_Value(Y))) &&
+          (FalseVal == X || FalseVal == Y))
+        return TrueVal;
+    }
+
     if (match(FalseVal, m_ZeroInt())) {
+      // !(X || Y) && X --> false (commuted 2 ways)
+      if (match(Cond, m_Not(m_LogicalOr(m_Value(X), m_Value(Y)))) &&
+          (TrueVal == X || TrueVal == Y))
+        return FalseVal;
+
+      // (X || Y) && (X || !Y) --> X (commuted 8 ways)
       if (match(Cond, m_c_LogicalOr(m_Value(X), m_Not(m_Value(Y)))) &&
           match(TrueVal, m_c_LogicalOr(m_Specific(X), m_Specific(Y))))
         return X;
Index: llvm/test/Transforms/InstSimplify/select-logical.ll
===================================================================
--- llvm/test/Transforms/InstSimplify/select-logical.ll
+++ llvm/test/Transforms/InstSimplify/select-logical.ll
@@ -122,3 +122,77 @@
   %and = select i1 %xorynot, i1 %xorz, i1 false
   ret i1 %and
 }
+
+; !(X || Y) && X --> false
+
+define i1 @logical_not_or_and(i1 %x, i1 %y) {
+; CHECK-LABEL: @logical_not_or_and(
+; CHECK-NEXT:    ret i1 false
+;
+  %l.and = select i1 %x, i1 true, i1 %y
+  %not = xor i1 %l.and, true
+  %r = select i1 %not, i1 %x, i1 false
+  ret i1 %r
+}
+
+
+; !(X || Y) && Y --> false
+
+define i1 @logical_not_or_and_case1(i1 %x, i1 %y) {
+; CHECK-LABEL: @logical_not_or_and_case1(
+; CHECK-NEXT:    ret i1 false
+;
+  %l.and = select i1 %x, i1 true, i1 %y
+  %not = xor i1 %l.and, true
+  %r = select i1 %not, i1 %y, i1 false
+  ret i1 %r
+}
+
+; negative test - must have common operands
+
+define i1 @logical_not_or_and_negative1(i1 %x, i1 %y, i1 %z) {
+; CHECK-LABEL: @logical_not_or_and_negative1(
+; CHECK-NEXT:    [[OR:%.*]] = or i1 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[OR]], i1 false, i1 [[Z:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %or = or i1 %x, %y
+  %r = select i1 %or, i1 false, i1 %z
+  ret i1 %r
+}
+
+
+; another way for !(X || Y) && X --> false
+
+define i1 @logical_not_or_and_case2(i1 %x, i1 %y) {
+; CHECK-LABEL: @logical_not_or_and_case2(
+; CHECK-NEXT:    ret i1 false
+;
+  %or = or i1 %x, %y
+  %r = select i1 %or, i1 false, i1 %x
+  ret i1 %r
+}
+
+; another way for !(X || Y) && Y --> false
+
+define i1 @logical_not_or_and_case3(i1 %x, i1 %y) {
+; CHECK-LABEL: @logical_not_or_and_case3(
+; CHECK-NEXT:    ret i1 false
+;
+  %or = or i1 %x, %y
+  %r = select i1 %or, i1 false, i1 %y
+  ret i1 %r
+}
+
+; negative test - must have common operands
+
+define i1 @logical_not_or_and_negative2(i1 %x, i1 %y, i1 %z) {
+; CHECK-LABEL: @logical_not_or_and_negative2(
+; CHECK-NEXT:    [[OR:%.*]] = or i1 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[OR]], i1 false, i1 [[Z:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %or = or i1 %x, %y
+  %r = select i1 %or, i1 false, i1 %z
+  ret i1 %r
+}