diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp --- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2673,6 +2673,7 @@ // A | ( A ^ B) -> A | B // A | (~A ^ B) -> A | ~B + // ~A | (A ^ B) -> ~(A & B) // (A & B) | (A ^ B) if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) { if (Op0 == A || Op0 == B) @@ -2682,6 +2683,10 @@ match(Op0, m_And(m_Specific(B), m_Specific(A)))) return BinaryOperator::CreateOr(A, B); + if (Op1->hasOneUse() && + (match(Op0, m_Not(m_Specific(A))) || match(Op0, m_Not(m_Specific(B))))) + return BinaryOperator::CreateNot(Builder.CreateAnd(A, B)); + if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) { Value *Not = Builder.CreateNot(B, B->getName() + ".not"); return BinaryOperator::CreateOr(Not, Op0); diff --git a/llvm/test/Transforms/InstCombine/and-or-icmps.ll b/llvm/test/Transforms/InstCombine/and-or-icmps.ll --- a/llvm/test/Transforms/InstCombine/and-or-icmps.ll +++ b/llvm/test/Transforms/InstCombine/and-or-icmps.ll @@ -369,12 +369,11 @@ ; CHECK-NEXT: [[B11:%.*]] = zext i1 [[TMP1]] to i16 ; CHECK-NEXT: [[C10:%.*]] = icmp ugt i16 [[L7]], [[B11]] ; CHECK-NEXT: [[C5:%.*]] = icmp slt i16 [[L7]], 1 -; CHECK-NEXT: [[C11:%.*]] = icmp ne i16 [[L7]], 0 ; CHECK-NEXT: [[C7:%.*]] = icmp slt i16 [[L7]], 0 ; CHECK-NEXT: [[B15:%.*]] = xor i1 [[C7]], [[C10]] -; CHECK-NEXT: [[B19:%.*]] = xor i1 [[C11]], [[B15]] +; CHECK-NEXT: [[C6:%.*]] = xor i1 [[B15]], true ; CHECK-NEXT: [[TMP2:%.*]] = and i1 [[C10]], [[C5]] -; CHECK-NEXT: [[C3:%.*]] = and i1 [[TMP2]], [[B19]] +; CHECK-NEXT: [[C3:%.*]] = and i1 [[TMP2]], [[C6]] ; CHECK-NEXT: [[TMP3:%.*]] = xor i1 [[C10]], true ; CHECK-NEXT: [[C18:%.*]] = or i1 [[C7]], [[TMP3]] ; CHECK-NEXT: [[TMP4:%.*]] = sext i1 [[C3]] to i64 diff --git a/llvm/test/Transforms/InstCombine/or-xor.ll b/llvm/test/Transforms/InstCombine/or-xor.ll --- a/llvm/test/Transforms/InstCombine/or-xor.ll +++ b/llvm/test/Transforms/InstCombine/or-xor.ll @@ -59,6 +59,20 @@ ret i32 %z } +; ~X | (X ^ Y) --> ~(X & Y) + +define i32 @test5(i32 %x, i32 %y) { +; CHECK-LABEL: @test5( +; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[Z:%.*]] = xor i32 [[TMP1]], -1 +; CHECK-NEXT: ret i32 [[Z]] +; + %xor = xor i32 %x, %y + %notx = xor i32 %x, -1 + %z = or i32 %xor, %notx + ret i32 %z +} + define i32 @test7(i32 %x, i32 %y) { ; CHECK-LABEL: @test7( ; CHECK-NEXT: [[Z:%.*]] = or i32 [[X:%.*]], [[Y:%.*]]