diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 682820a25ca..381a687aca1 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2692,6 +2692,26 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { return new ICmpInst(I.getPredicate(), A, B); } + // (icmp sgt (sub nsw A B), -1) -> (icmp sge A, B) + if (I.getPredicate() == ICmpInst::ICMP_SGT && CI->isAllOnesValue() && + match(Op0, m_NSWSub(m_Value(A), m_Value(B)))) + return new ICmpInst(ICmpInst::ICMP_SGE, A, B); + + // (icmp sgt (sub nsw A B), 0) -> (icmp sgt A, B) + if (I.getPredicate() == ICmpInst::ICMP_SGT && CI->isZero() && + match(Op0, m_NSWSub(m_Value(A), m_Value(B)))) + return new ICmpInst(ICmpInst::ICMP_SGT, A, B); + + // (icmp slt (sub nsw A B), 0) -> (icmp slt A, B) + if (I.getPredicate() == ICmpInst::ICMP_SLT && CI->isZero() && + match(Op0, m_NSWSub(m_Value(A), m_Value(B)))) + return new ICmpInst(ICmpInst::ICMP_SLT, A, B); + + // (icmp slt (sub nsw A B), 1) -> (icmp sle A, B) + if (I.getPredicate() == ICmpInst::ICMP_SLT && CI->isOne() && + match(Op0, m_NSWSub(m_Value(A), m_Value(B)))) + return new ICmpInst(ICmpInst::ICMP_SLE, A, B); + // If we have an icmp le or icmp ge instruction, turn it into the // appropriate icmp lt or icmp gt instruction. This allows us to rely on // them being folded in the code below. The SimplifyICmpInst code has |
