6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-26 21:32:10 +00:00
Code Issues Projects Releases Wiki Activity

Thread divisions over selects and phis. This doesn't fire much and has basically

Browse Source 
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
This commit is contained in:
Duncan Sands 2011-01-28 18:50:50 +00:00
parent d11c57a937
commit a3e292c7e8
1 changed files with 19 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
lib/Analysis/InstructionSimplify.cpp
View File

@ -759,6 +759,8 @@ static Value *SimplifyDiv(unsigned Opcode, Value *Op0, Value *Op1,
}
}
bool isSigned = Opcode == Instruction::SDiv;
// X / undef -> undef
if (isa<UndefValue>(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<BinaryOperator>(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<SelectInst>(Op0) || isa<SelectInst>(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<PHINode>(Op0) || isa<PHINode>(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;
}