From a3e292c7e85efb33899f08238f57a85996a05a0b Mon Sep 17 00:00:00 2001 From: Duncan Sands Date: Fri, 28 Jan 2011 18:50:50 +0000 Subject: [PATCH] Thread divisions over selects and phis. This doesn't fire much and has basically zero effect on the testsuite (it improves two Ada testcases). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124496 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/InstructionSimplify.cpp | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 790b619814c..54dc6e6148e 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -759,6 +759,8 @@ static Value *SimplifyDiv(unsigned Opcode, Value *Op0, Value *Op1, } } + bool isSigned = Opcode == Instruction::SDiv; + // X / undef -> undef if (isa(Op1)) return Op1; @@ -795,7 +797,6 @@ static Value *SimplifyDiv(unsigned Opcode, Value *Op0, Value *Op1, if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1 BinaryOperator *Mul = dyn_cast(Op0); // If the Mul knows it does not overflow, then we are good to go. - bool isSigned = Opcode == Instruction::SDiv; if ((isSigned && Mul->hasNoSignedWrap()) || (!isSigned && Mul->hasNoUnsignedWrap())) return X; @@ -805,6 +806,23 @@ static Value *SimplifyDiv(unsigned Opcode, Value *Op0, Value *Op1, return X; } + // (X rem Y) / Y -> 0 + if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) || + (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1))))) + return Constant::getNullValue(Op0->getType()); + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa(Op0) || isa(Op1)) + if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa(Op0) || isa(Op1)) + if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse)) + return V; + return 0; } @@ -815,10 +833,6 @@ static Value *SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD, if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, TD, DT, MaxRecurse)) return V; - // (X rem Y) / Y -> 0 - if (match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) - return Constant::getNullValue(Op0->getType()); - return 0; } @@ -834,10 +848,6 @@ static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD, if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, TD, DT, MaxRecurse)) return V; - // (X rem Y) / Y -> 0 - if (match(Op0, m_URem(m_Value(), m_Specific(Op1)))) - return Constant::getNullValue(Op0->getType()); - return 0; }