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Merged
tannergooding merged 2 commits into from
May 4, 2026
+29 −13
Merged

Ensure we preserve vn and produce a canonical tree #127689

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b938c26
Ensure we preserve vn and produce a canonical tree
tannergooding May 2, 2026
a2a38d1
PRESERVE_VN in a few more places
tannergooding May 3, 2026
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42 changes: 29 additions & 13 deletions src/coreclr/jit/morph.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6736,6 +6736,7 @@ GenTree* Compiler::fgMorphLeaf(GenTree* tree)
tree->SetOper(GT_CNS_INT);
tree->AsIntConCommon()->SetIconValue(ssize_t(addrInfo.handle));
tree->gtFlags |= GTF_ICON_FTN_ADDR;
fgUpdateConstTreeValueNumber(tree);
INDEBUG(tree->AsIntCon()->gtTargetHandle = reinterpret_cast<size_t>(funcHandle));
break;

Expand Down Expand Up @@ -7484,7 +7485,7 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
JITDUMP("\nTransforming:\n");
DISPTREE(tree);

otherNode->SetOper(GT_AND); // Change % => &
otherNode->SetOper(GT_AND, GenTree::PRESERVE_VN); // Change % => &
otherNode->gtFlags &= ~(GTF_DIV_MOD_NO_OVERFLOW | GTF_DIV_MOD_NO_BY_ZERO);

divisor->AsIntConCommon()->SetIconValue(modValue - 1); // Change c => c - 1
Expand Down Expand Up @@ -7902,11 +7903,11 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
fgUpdateConstTreeValueNumber(op2);

oper = GT_ADD;
tree->ChangeOper(oper);
tree->ChangeOper(oper, GenTree::PRESERVE_VN);
goto CM_ADD_OP;
}

/* Check for "cns1 - op2" , we change it to "(cns1 + (-op2))" */
/* Check for "cns1 - op2" , we change it to "((-op2) + cns1)" */
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noway_assert(op1);
if (op1->IsCnsIntOrI())
Expand All @@ -7919,7 +7920,7 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
// GT_CAST<ubyte>(GT_SUB(0, s_1.ubyte))
if (op1->IsIntegralConst(0))
{
tree->ChangeOper(GT_NEG);
tree->ChangeOper(GT_NEG, GenTree::PRESERVE_VN);
tree->gtType = genActualType(op2->TypeGet());

tree->AsOp()->gtOp1 = op2;
Expand All @@ -7929,11 +7930,15 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
return tree;
}

tree->AsOp()->gtOp2 = op2 = gtNewOperNode(GT_NEG, genActualType(op2->TypeGet()), op2);
op2 = gtNewOperNode(GT_NEG, genActualType(op2->TypeGet()), op2);
fgMorphTreeDone(op2);

std::swap(op2, op1);
tree->AsOp()->gtOp1 = op1;
tree->AsOp()->gtOp2 = op2;

oper = GT_ADD;
tree->ChangeOper(oper);
tree->ChangeOper(oper, GenTree::PRESERVE_VN);
goto CM_ADD_OP;
}
}
Expand Down Expand Up @@ -8061,8 +8066,9 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA

if (transform)
{
tree->ChangeOper(GT_MUL);
tree->ChangeOper(GT_MUL, GenTree::PRESERVE_VN);
op2->AsDblCon()->SetDconValue(divisor);
fgUpdateConstTreeValueNumber(op2);

oper = GT_MUL;
goto CM_OVF_OP;
Expand Down Expand Up @@ -8925,6 +8931,7 @@ GenTree* Compiler::fgOptimizeEqualityComparisonWithConst(GenTreeOp* cmp)
{
goto SKIP; // Unsupported type or invalid shift amount.
}
fgUpdateConstTreeValueNumber(andMask);
andOp->gtOp1 = rshiftOp->gtGetOp1();

DEBUG_DESTROY_NODE(rshiftOp->gtGetOp2());
Expand Down Expand Up @@ -8957,6 +8964,7 @@ GenTree* Compiler::fgOptimizeEqualityComparisonWithConst(GenTreeOp* cmp)
{
gtReverseCond(cmp);
op2->SetIntegralValue(0);
fgUpdateConstTreeValueNumber(op2);
}
}
}
Expand Down Expand Up @@ -10109,6 +10117,7 @@ GenTree* Compiler::fgOptimizeHWIntrinsic(GenTreeHWIntrinsic* node)
{
ExtractEffectiveOp(GT_NOT, node, /* destroyNodes */ true);
cmpOp3->AsIntConCommon()->SetIntegralValue(static_cast<uint8_t>(mode));
fgUpdateConstTreeValueNumber(cmpOp3);
return fgMorphHWIntrinsicRequired(op1Intrin);
}
break;
Expand Down Expand Up @@ -10663,7 +10672,7 @@ GenTree* Compiler::fgOptimizeMultiply(GenTreeOp* mul)
}
else
{
mul->ChangeOper(GT_NEG);
mul->ChangeOper(GT_NEG, GenTree::PRESERVE_VN);
mul->AsOp()->gtOp2 = nullptr;
return mul;
}
Expand Down Expand Up @@ -10995,7 +11004,7 @@ GenTree* Compiler::fgOptimizeBitwiseXor(GenTreeOp* xorOp)
else if (op2->IsIntegralConst(-1))
{
/* "x ^ -1" is "~x" */
xorOp->ChangeOper(GT_NOT);
xorOp->ChangeOper(GT_NOT, GenTree::PRESERVE_VN);
xorOp->gtOp2 = nullptr;
DEBUG_DESTROY_NODE(op2);

Expand All @@ -11014,7 +11023,7 @@ GenTree* Compiler::fgOptimizeBitwiseXor(GenTreeOp* xorOp)
{
// "x ^ -0.0" is "-x"

xorOp->ChangeOper(GT_NEG);
xorOp->ChangeOper(GT_NEG, GenTree::PRESERVE_VN);
xorOp->gtOp2 = nullptr;

DEBUG_DESTROY_NODE(op2);
Expand Down Expand Up @@ -11323,13 +11332,16 @@ GenTree* Compiler::fgMorphSmpOpOptional(GenTreeOp* tree, bool* optAssertionPropD
/* Change '(val + iadd) * imul' -> '(val * imul) + (iadd * imul)' */

oper = GT_ADD;
tree->ChangeOper(oper);
tree->ChangeOper(oper, GenTree::PRESERVE_VN);

op2->AsIntCon()->SetValueTruncating(iadd * imul);
fgUpdateConstTreeValueNumber(op2);

// changing from (val + iadd) to (val * imul), so don't preserve VN
op1->ChangeOper(GT_MUL);

add->AsIntCon()->SetIconValue(imul);
fgValueNumberTreeConst(add);
}
}

Expand Down Expand Up @@ -11368,13 +11380,17 @@ GenTree* Compiler::fgMorphSmpOpOptional(GenTreeOp* tree, bool* optAssertionPropD

/* Change "(val + iadd) << ishf" into "(val<<ishf + iadd<<ishf)" */

tree->ChangeOper(GT_ADD);
tree->ChangeOper(GT_ADD, GenTree::PRESERVE_VN);

// we are reusing the shift amount node here, but the type we want is that of the shift result
op2->gtType = op1->gtType;
op2->AsIntConCommon()->SetValueTruncating(iadd << ishf);
fgUpdateConstTreeValueNumber(op2);

// changing from (val + iadd) to (val << ishf), so don't preserve VN
op1->ChangeOper(GT_LSH);
cns->AsIntConCommon()->SetIconValue(ishf);
fgUpdateConstTreeValueNumber(cns);
}
}

Expand Down Expand Up @@ -12396,7 +12412,7 @@ GenTree* Compiler::fgRecognizeAndMorphBitwiseRotation(GenTree* tree)
{
tree->AsOp()->gtOp1 = rotatedValue;
tree->AsOp()->gtOp2 = rotateIndex;
tree->ChangeOper(rotateOp);
tree->ChangeOper(rotateOp, GenTree::PRESERVE_VN);

unsigned childFlags = 0;
for (GenTree* op : tree->Operands())
Expand Down
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