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Remove fgMorphCastedBitwiseOp #86491

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May 19, 2023
+0 −79
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Remove fgMorphCastedBitwiseOp #86491

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1 change: 0 additions & 1 deletion src/coreclr/jit/compiler.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5997,7 +5997,6 @@ class Compiler
GenTree* fgMorphConst(GenTree* tree);

GenTreeOp* fgMorphCommutative(GenTreeOp* tree);
GenTree* fgMorphCastedBitwiseOp(GenTreeOp* tree);

GenTree* fgMorphReduceAddOps(GenTree* tree);

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78 changes: 0 additions & 78 deletions src/coreclr/jit/morph.cpp
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Expand Up @@ -8347,75 +8347,6 @@ GenTreeOp* Compiler::fgMorphCommutative(GenTreeOp* tree)
return op1->AsOp();
}

//------------------------------------------------------------------------------
// fgMorphCastedBitwiseOp : Try to simplify "(T)x op (T)y" to "(T)(x op y)".
//
// Arguments:
// tree - node to fold
//
// Return Value:
// A folded GenTree* instance, or nullptr if it couldn't be folded
GenTree* Compiler::fgMorphCastedBitwiseOp(GenTreeOp* tree)
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Not for this PR, but is this something we can handle in lowering instead where we can make the decision to keep or bypass the cast based on whether the operands are coming from memory?

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Probably, let's see if perf triage will find any regressions (hoping to see improvements instead)

{
// This transform does not preserve VNs and deletes a node.
assert(fgGlobalMorph);
assert(varTypeIsIntegralOrI(tree));
assert(tree->OperIs(GT_OR, GT_AND, GT_XOR));

GenTree* op1 = tree->gtGetOp1();
GenTree* op2 = tree->gtGetOp2();
genTreeOps oper = tree->OperGet();

// see whether both ops are casts, with matching to and from types.
if (op1->OperIs(GT_CAST) && op2->OperIs(GT_CAST))
{
// bail if either operand is a checked cast
if (op1->gtOverflow() || op2->gtOverflow())
{
return nullptr;
}

var_types fromType = op1->AsCast()->CastOp()->TypeGet();
var_types toType = op1->AsCast()->CastToType();
bool isUnsigned = op1->IsUnsigned();

if (varTypeIsFloating(fromType) || (op2->CastFromType() != fromType) || (op2->CastToType() != toType) ||
(op2->IsUnsigned() != isUnsigned))
{
return nullptr;
}

/*
// Reuse gentree nodes:
//
// tree op1
// / \ |
// op1 op2 ==> tree
// | | / \.
// x y x y
//
// (op2 becomes garbage)
*/

tree->gtOp1 = op1->AsCast()->CastOp();
tree->gtOp2 = op2->AsCast()->CastOp();
tree->gtType = genActualType(fromType);

op1->gtType = genActualType(toType);
op1->AsCast()->gtOp1 = tree;
op1->AsCast()->CastToType() = toType;
op1->SetAllEffectsFlags(tree);
// no need to update isUnsigned

DEBUG_DESTROY_NODE(op2);
INDEBUG(op1->gtDebugFlags |= GTF_DEBUG_NODE_MORPHED);

return op1;
}

return nullptr;
}

//------------------------------------------------------------------------
// fgMorphSmpOp: morph a GTK_SMPOP tree
//
Expand Down Expand Up @@ -10862,15 +10793,6 @@ GenTree* Compiler::fgOptimizeCommutativeArithmetic(GenTreeOp* tree)
}
}

if (fgGlobalMorph && tree->OperIs(GT_AND, GT_OR, GT_XOR))
{
GenTree* castTree = fgMorphCastedBitwiseOp(tree->AsOp());
if (castTree != nullptr)
{
return castTree;
}
}

if (varTypeIsIntegralOrI(tree))
{
genTreeOps oldTreeOper = tree->OperGet();
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