Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp =================================================================== --- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -3371,6 +3371,10 @@ match(Op1, m_Not(m_Specific(A)))) return BinaryOperator::CreateNot(Builder.CreateAnd(A, B)); + // (~A & B) ^ A --> (A | B) -- There are 4 commuted variants. + if (match(&I, m_c_Xor(m_c_And(m_Not(m_Value(A)), m_Value(B)), m_Deferred(A)))) + return BinaryOperator::CreateOr(A, B); + // (A | B) ^ (A | C) --> (B ^ C) & ~A -- There are 4 commuted variants. // TODO: Loosen one-use restriction if common operand is a constant. Value *D; Index: llvm/test/Transforms/InstCombine/xor.ll =================================================================== --- llvm/test/Transforms/InstCombine/xor.ll +++ llvm/test/Transforms/InstCombine/xor.ll @@ -1179,9 +1179,7 @@ ; CHECK-LABEL: @test52( ; CHECK-NEXT: [[A:%.*]] = udiv i32 42, [[P1:%.*]] ; CHECK-NEXT: [[B:%.*]] = udiv i32 42, [[P2:%.*]] -; CHECK-NEXT: [[O:%.*]] = xor i32 [[A]], -1 -; CHECK-NEXT: [[R:%.*]] = and i32 [[B]], [[O]] -; CHECK-NEXT: [[Z:%.*]] = xor i32 [[R]], [[A]] +; CHECK-NEXT: [[Z:%.*]] = or i32 [[A]], [[B]] ; CHECK-NEXT: ret i32 [[Z]] ; %a = udiv i32 42, %p1 @@ -1192,33 +1190,11 @@ ret i32 %z } -; (~B & A) ^ B --> (A | B) -; The division ops are here to thwart complexity-based canonicalization: all ops are binops. - define i32 @test53(i32 %p1, i32 %p2) { ; CHECK-LABEL: @test53( ; CHECK-NEXT: [[A:%.*]] = udiv i32 42, [[P1:%.*]] ; CHECK-NEXT: [[B:%.*]] = udiv i32 42, [[P2:%.*]] -; CHECK-NEXT: [[O:%.*]] = xor i32 [[B]], -1 -; CHECK-NEXT: [[R:%.*]] = and i32 [[A]], [[O]] -; CHECK-NEXT: [[Z:%.*]] = xor i32 [[R]], [[B]] -; CHECK-NEXT: ret i32 [[Z]] -; - %a = udiv i32 42, %p1 - %b = udiv i32 42, %p2 - %o = xor i32 %b, -1 - %r = and i32 %o, %a - %z = xor i32 %r, %b - ret i32 %z -} - -define i32 @test54(i32 %p1, i32 %p2) { -; CHECK-LABEL: @test54( -; CHECK-NEXT: [[A:%.*]] = udiv i32 42, [[P1:%.*]] -; CHECK-NEXT: [[B:%.*]] = udiv i32 42, [[P2:%.*]] -; CHECK-NEXT: [[O:%.*]] = xor i32 [[A]], -1 -; CHECK-NEXT: [[R:%.*]] = and i32 [[B]], [[O]] -; CHECK-NEXT: [[Z:%.*]] = xor i32 [[R]], [[A]] +; CHECK-NEXT: [[Z:%.*]] = or i32 [[A]], [[B]] ; CHECK-NEXT: ret i32 [[Z]] ; %a = udiv i32 42, %p1 @@ -1228,20 +1204,3 @@ %z = xor i32 %r, %a ret i32 %z } - -define i32 @test55(i32 %p1, i32 %p2) { -; CHECK-LABEL: @test55( -; CHECK-NEXT: [[A:%.*]] = udiv i32 42, [[P1:%.*]] -; CHECK-NEXT: [[B:%.*]] = udiv i32 42, [[P2:%.*]] -; CHECK-NEXT: [[O:%.*]] = xor i32 [[A]], -1 -; CHECK-NEXT: [[R:%.*]] = and i32 [[B]], [[O]] -; CHECK-NEXT: [[Z:%.*]] = xor i32 [[A]], [[R]] -; CHECK-NEXT: ret i32 [[Z]] -; - %a = udiv i32 42, %p1 - %b = udiv i32 42, %p2 - %o = xor i32 %a, -1 - %r = and i32 %o, %b - %z = xor i32 %a, %r - ret i32 %z -}