diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 404b53db86..f55aff3125 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -45,6 +45,7 @@ #include "llvm/Transforms/Utils/BasicBlockUtils.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Support/CallSite.h" +#include "llvm/Support/ConstantRange.h" #include "llvm/Support/Debug.h" #include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/InstVisitor.h" @@ -5704,6 +5705,37 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, DivRHS)) return R; break; + + case Instruction::Add: + // Fold: icmp pred (add, X, C1), C2 + + if (!ICI.isEquality()) { + ConstantInt *LHSC = dyn_cast<ConstantInt>(LHSI->getOperand(1)); + if (!LHSC) break; + const APInt &LHSV = LHSC->getValue(); + + ConstantRange CR = ICI.makeConstantRange(ICI.getPredicate(), RHSV) + .subtract(LHSV); + + if (ICI.isSignedPredicate()) { + if (CR.getLower().isSignBit()) { + return new ICmpInst(ICmpInst::ICMP_SLT, LHSI->getOperand(0), + ConstantInt::get(CR.getUpper())); + } else if (CR.getUpper().isSignBit()) { + return new ICmpInst(ICmpInst::ICMP_SGE, LHSI->getOperand(0), + ConstantInt::get(CR.getLower())); + } + } else { + if (CR.getLower().isMinValue()) { + return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0), + ConstantInt::get(CR.getUpper())); + } else if (CR.getUpper().isMinValue()) { + return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0), + ConstantInt::get(CR.getLower())); + } + } + } + break; } // Simplify icmp_eq and icmp_ne instructions with integer constant RHS. |