diff options
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineAndOrXor.cpp')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 32 |
1 files changed, 7 insertions, 25 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 372bc41f780e..3d758e2fe7c9 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1550,31 +1550,13 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { return DeMorgan; { - Value *A = nullptr, *B = nullptr, *C = nullptr; - // A&(A^B) => A & ~B - { - Value *tmpOp0 = Op0; - Value *tmpOp1 = Op1; - if (match(Op0, m_OneUse(m_Xor(m_Value(A), m_Value(B))))) { - if (A == Op1 || B == Op1 ) { - tmpOp1 = Op0; - tmpOp0 = Op1; - // Simplify below - } - } - - if (match(tmpOp1, m_OneUse(m_Xor(m_Value(A), m_Value(B))))) { - if (B == tmpOp0) { - std::swap(A, B); - } - // Notice that the pattern (A&(~B)) is actually (A&(-1^B)), so if - // A is originally -1 (or a vector of -1 and undefs), then we enter - // an endless loop. By checking that A is non-constant we ensure that - // we will never get to the loop. - if (A == tmpOp0 && !isa<Constant>(A)) // A&(A^B) -> A & ~B - return BinaryOperator::CreateAnd(A, Builder.CreateNot(B)); - } - } + Value *A, *B, *C; + // A & (A ^ B) --> A & ~B + if (match(Op1, m_OneUse(m_c_Xor(m_Specific(Op0), m_Value(B))))) + return BinaryOperator::CreateAnd(Op0, Builder.CreateNot(B)); + // (A ^ B) & A --> A & ~B + if (match(Op0, m_OneUse(m_c_Xor(m_Specific(Op1), m_Value(B))))) + return BinaryOperator::CreateAnd(Op1, Builder.CreateNot(B)); // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C if (match(Op0, m_Xor(m_Value(A), m_Value(B)))) |