diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index 4d5fa8776e..4c252c03d0 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2669,6 +2669,15 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { } { Value *A, *B; + // Transform (A & ~B) == 0 --> (A & B) != 0 + // and (A & ~B) != 0 --> (A & B) == 0 + // if A is a power of 2. + if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) && + match(Op1, m_Zero()) && isKnownToBeAPowerOfTwo(A) && I.isEquality()) + return new ICmpInst(I.getInversePredicate(), + Builder->CreateAnd(A, B), + Op1); + // ~x < ~y --> y < x // ~x < cst --> ~cst < x if (match(Op0, m_Not(m_Value(A)))) { |