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Small TP improvement in assertprop #113360

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Merged
merged 3 commits into from
Mar 12, 2025
Merged

Small TP improvement in assertprop #113360

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d8fc101
Small TP improvement in assertprop
EgorBo Mar 11, 2025
1ca2b26
Add "is addr exposed" check back
EgorBo Mar 11, 2025
88f6326
Refactor exception check for indirection faults
EgorBo Mar 12, 2025
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87 changes: 29 additions & 58 deletions src/coreclr/jit/assertionprop.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1130,39 +1130,28 @@ AssertionIndex Compiler::optCreateAssertion(GenTree* op1, GenTree* op2, optAsser
AssertionDsc assertion = {OAK_INVALID};
assert(assertion.assertionKind == OAK_INVALID);

if (op1->OperIs(GT_BOUNDS_CHECK))
if (op1->OperIs(GT_BOUNDS_CHECK) && (assertionKind == OAK_NO_THROW))
{
if (assertionKind == OAK_NO_THROW)
{
GenTreeBoundsChk* arrBndsChk = op1->AsBoundsChk();
assertion.assertionKind = assertionKind;
assertion.op1.kind = O1K_ARR_BND;
assertion.op1.bnd.vnIdx = optConservativeNormalVN(arrBndsChk->GetIndex());
assertion.op1.bnd.vnLen = optConservativeNormalVN(arrBndsChk->GetArrayLength());

if ((assertion.op1.bnd.vnIdx == ValueNumStore::NoVN) || (assertion.op1.bnd.vnLen == ValueNumStore::NoVN))
{
// Don't make an assertion if one of the operands has no VN
return NO_ASSERTION_INDEX;
}

goto DONE_ASSERTION;
}
GenTreeBoundsChk* arrBndsChk = op1->AsBoundsChk();
assertion.assertionKind = assertionKind;
assertion.op1.kind = O1K_ARR_BND;
assertion.op1.bnd.vnIdx = optConservativeNormalVN(arrBndsChk->GetIndex());
assertion.op1.bnd.vnLen = optConservativeNormalVN(arrBndsChk->GetArrayLength());
}

//
// Are we trying to make a non-null assertion?
//
if (op2 == nullptr)
else if (op2 == nullptr)
{
//
if (!varTypeIsGC(op1))
{
return NO_ASSERTION_INDEX; // Don't make an assertion
}

// Must be an OAK_NOT_EQUAL assertion
//
noway_assert(assertionKind == OAK_NOT_EQUAL);
assert(assertionKind == OAK_NOT_EQUAL);

//
// Set op1 to the instance pointer of the indirection
//
op1 = op1->gtEffectiveVal();

ssize_t offset = 0;
Expand All @@ -1184,39 +1173,18 @@ AssertionIndex Compiler::optCreateAssertion(GenTree* op1, GenTree* op2, optAsser
}
}

if (fgIsBigOffset(offset) || op1->gtOper != GT_LCL_VAR)
if (!fgIsBigOffset(offset) && op1->OperIs(GT_LCL_VAR) && !lvaVarAddrExposed(op1->AsLclVar()->GetLclNum()))
{
goto DONE_ASSERTION; // Don't make an assertion
}

unsigned lclNum = op1->AsLclVarCommon()->GetLclNum();
LclVarDsc* lclVar = lvaGetDesc(lclNum);

ValueNum vn;

// We only perform null-checks on byrefs and GC refs
if (!varTypeIsGC(lclVar->TypeGet()))
{
goto DONE_ASSERTION; // Don't make an assertion
}

// If the local variable has its address exposed then bail
if (lclVar->IsAddressExposed())
{
goto DONE_ASSERTION; // Don't make an assertion
assertion.op1.kind = O1K_LCLVAR;
assertion.op1.lcl.lclNum = op1->AsLclVarCommon()->GetLclNum();
assertion.op1.lcl.ssaNum = op1->AsLclVarCommon()->GetSsaNum();
assertion.op1.vn = optConservativeNormalVN(op1);
assertion.assertionKind = assertionKind;
assertion.op2.kind = O2K_CONST_INT;
assertion.op2.vn = ValueNumStore::VNForNull();
assertion.op2.u1.iconVal = 0;
assertion.op2.SetIconFlag(GTF_EMPTY);
}

assertion.op1.kind = O1K_LCLVAR;
assertion.op1.lcl.lclNum = lclNum;
assertion.op1.lcl.ssaNum = op1->AsLclVarCommon()->GetSsaNum();
vn = optConservativeNormalVN(op1);

assertion.op1.vn = vn;
assertion.assertionKind = assertionKind;
assertion.op2.kind = O2K_CONST_INT;
assertion.op2.vn = ValueNumStore::VNForNull();
assertion.op2.u1.iconVal = 0;
assertion.op2.SetIconFlag(GTF_EMPTY);
}
//
// Are we making an assertion about a local variable?
Expand Down Expand Up @@ -1431,8 +1399,7 @@ AssertionIndex Compiler::optCreateAssertion(GenTree* op1, GenTree* op2, optAsser
ValueNum op2VN = optConservativeNormalVN(op2);

// For TP reasons, limited to 32-bit constants on the op2 side.
if ((op1VN != ValueNumStore::NoVN) && (op2VN != ValueNumStore::NoVN) && vnStore->IsVNInt32Constant(op2VN) &&
!vnStore->IsVNHandle(op2VN))
if (vnStore->IsVNInt32Constant(op2VN) && !vnStore->IsVNHandle(op2VN))
{
assert(assertionKind == OAK_EQUAL || assertionKind == OAK_NOT_EQUAL);
assertion.assertionKind = assertionKind;
Expand Down Expand Up @@ -2370,7 +2337,11 @@ void Compiler::optAssertionGen(GenTree* tree)
case GT_ARR_LENGTH:
case GT_MDARR_LENGTH:
case GT_MDARR_LOWER_BOUND:
assertionInfo = optCreateAssertion(tree->GetIndirOrArrMetaDataAddr(), nullptr, OAK_NOT_EQUAL);
// These indirs (esp. GT_IND and GT_STOREIND) are the most popular sources of assertions.
if ((tree->gtFlags & GTF_EXCEPT) != 0)
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Seems it might make more sense to use IndirMayFault() here, since this check conflates the exceptions thrown by operands with the indir itself.

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@EgorBo EgorBo Mar 12, 2025 •
edited
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Good point, but looks like IndirMayFault may not be cheap. In this case it's just a heuristic to avoid creating too many assertions (and we do create too many)

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Although, I'll check

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Addressed

{
assertionInfo = optCreateAssertion(tree->GetIndirOrArrMetaDataAddr(), nullptr, OAK_NOT_EQUAL);
}
break;

case GT_INTRINSIC:
Expand Down
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