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Move optimization of some cases of (A & C1)|(B & C2) from instcombine to instsimplify. Patch by Rahul Jain, plus some last minute changes by me -- you can blame me for any bugs.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211252 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky
2014-06-19 03:51:46 +00:00
parent 650b6ea893
commit fe3a219355
3 changed files with 69 additions and 23 deletions
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32
lib/Analysis/InstructionSimplify.cpp
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@@ -1625,6 +1625,38 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
MaxRecurse))
return V;
// (A & C)|(B & D)
Value *C = nullptr, *D = nullptr;
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
match(Op1, m_And(m_Value(B), m_Value(D)))) {
ConstantInt *C1 = dyn_cast<ConstantInt>(C);
ConstantInt *C2 = dyn_cast<ConstantInt>(D);
if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
// (A & C1)|(B & C2)
// If we have: ((V + N) & C1) | (V & C2)
// .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
// replace with V+N.
Value *V1, *V2;
if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
match(A, m_Add(m_Value(V1), m_Value(V2)))) {
// Add commutes, try both ways.
if (V1 == B && MaskedValueIsZero(V2, C2->getValue()))
return A;
if (V2 == B && MaskedValueIsZero(V1, C2->getValue()))
return A;
}
// Or commutes, try both ways.
if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
match(B, m_Add(m_Value(V1), m_Value(V2)))) {
// Add commutes, try both ways.
if (V1 == A && MaskedValueIsZero(V2, C1->getValue()))
return B;
if (V2 == A && MaskedValueIsZero(V1, C1->getValue()))
return B;
}
}
}
// 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))