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JIT: Optimize *x = dblCns to *x = intCns #52298

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Merged
EgorBo merged 10 commits into from
May 18, 2021
Merged

JIT: Optimize *x = dblCns to *x = intCns #52298

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d01c0ce
Optimize *x = 0.0
EgorBo May 5, 2021
da5a07b
Address feedback
EgorBo May 5, 2021
6ca1ed9
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EgorBo May 5, 2021
f07248c
Handle any constant
EgorBo May 5, 2021
e1800e1
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EgorBo May 5, 2021
ed88569
Merge branch 'main' of github.com:dotnet/runtime into jit-opt-store-z…
EgorBo May 5, 2021
2e147e7
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EgorBo May 5, 2021
c393e95
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EgorBo May 5, 2021
c8d3b49
Update lowerxarch.cpp
EgorBo May 5, 2021
6e047a4
Update lowerxarch.cpp
EgorBo May 5, 2021
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32 changes: 32 additions & 0 deletions src/coreclr/jit/lowerxarch.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,38 @@ void Lowering::LowerStoreIndir(GenTreeIndir* node)
return;
}
}
else if (node->AsStoreInd()->Data()->OperIs(GT_CNS_DBL))
{
// Optimize *x = DCON to *x = ICON which is slightly faster on xarch
GenTree* data = node->AsStoreInd()->Data();
double dblCns = data->AsDblCon()->gtDconVal;
ssize_t intCns = 0;
var_types type = TYP_UNKNOWN;

if (node->TypeIs(TYP_FLOAT))
{
float fltCns = static_cast<float>(dblCns); // should be a safe round-trip
intCns = static_cast<ssize_t>(*reinterpret_cast<UINT32*>(&fltCns));
type = TYP_UINT;
}
#ifdef TARGET_AMD64
else
{
assert(node->TypeIs(TYP_DOUBLE));
intCns = static_cast<ssize_t>(*reinterpret_cast<UINT64*>(&dblCns));
type = TYP_ULONG;
}
#endif

if (type != TYP_UNKNOWN)
{
data->SetContained();
data->ChangeOperConst(GT_CNS_INT);
data->AsIntCon()->SetIconValue(intCns);
data->ChangeType(type);
node->ChangeType(type);
}
}
ContainCheckStoreIndir(node);
}

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