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Enable constant folding in Tier0 #82412

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merged 2 commits into from Feb 24, 2023
Merged

Enable constant folding in Tier0 #82412

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7c1cb32
Enable constant folding in tier0
EgorBo Feb 20, 2023
777aadf
Address feedback
EgorBo Feb 21, 2023
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30 changes: 4 additions & 26 deletions src/coreclr/jit/fgprofile.cpp
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Expand Up @@ -1448,34 +1448,12 @@ void EfficientEdgeCountInstrumentor::SplitCriticalEdges()
JITDUMP("Could not find " FMT_BB " -> " FMT_BB " edge to instrument\n", block->bbNum,
target->bbNum);

// If we're optimizing, assume this edge got folded away
//
if (m_comp->opts.IsInstrumentedOptimized())
{
JITDUMP(" -- assuming this edge was folded away by the importer\n");
JITDUMP(" -- assuming this edge was folded away by the importer\n");

// Placate the asserts below
//
instrumentedBlock = source;
edgesIgnored++;
}
// If the source block is a partial compilation patchpoint
// then the edge will have been removed.
// Placate the asserts below
//
else if ((block->bbFlags & BBF_PARTIAL_COMPILATION_PATCHPOINT) ==
BBF_PARTIAL_COMPILATION_PATCHPOINT)
{
JITDUMP(" -- source block is partial compilation patchpoint\n");

// Placate the asserts below
//
instrumentedBlock = source;
edgesIgnored++;
}
else
{
assert(found);
}
instrumentedBlock = source;
edgesIgnored++;
}

// Delete the critical edge probe
Expand Down
20 changes: 13 additions & 7 deletions src/coreclr/jit/gentree.cpp
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Expand Up @@ -6085,9 +6085,6 @@ unsigned GenTree::GetScaleIndexShf()

unsigned GenTree::GetScaledIndex()
{
// with (!opts.OptEnabled(CLFLG_CONSTANTFOLD) we can have
// CNS_INT * CNS_INT
//
if (AsOp()->gtOp1->IsCnsIntOrI())
{
return 0;
Expand Down Expand Up @@ -12853,6 +12850,14 @@ GenTree* Compiler::gtFoldExpr(GenTree* tree)
return tree;
}

// NOTE: MinOpts() is always true for Tier0 so we have to check explicit flags instead.
// To be fixed in https://github.com/dotnet/runtime/pull/77465
const bool tier0opts = !opts.compDbgCode && !opts.jitFlags->IsSet(JitFlags::JIT_FLAG_MIN_OPT);
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We have an explicit Tier0 flag, why not check this?

if (!tier0opts)
{
return tree;
}

if (!(kind & GTK_SMPOP))
{
if (tree->OperIsConditional())
Expand Down Expand Up @@ -12886,9 +12891,7 @@ GenTree* Compiler::gtFoldExpr(GenTree* tree)
return gtFoldExprConst(tree);
}
}
else if ((kind & GTK_BINOP) && op1 && tree->AsOp()->gtOp2 &&
// Don't take out conditionals for debugging
(opts.OptimizationEnabled() || !tree->OperIsCompare()))
else if ((kind & GTK_BINOP) && op1 && tree->AsOp()->gtOp2)
{
GenTree* op2 = tree->AsOp()->gtOp2;

Expand Down Expand Up @@ -14552,7 +14555,10 @@ GenTree* Compiler::gtFoldExprConst(GenTree* tree)
GenTree* op1 = tree->gtGetOp1();
GenTree* op2 = tree->gtGetOp2IfPresent();

if (!opts.OptEnabled(CLFLG_CONSTANTFOLD))
// NOTE: MinOpts() is always true for Tier0 so we have to check explicit flags instead.
// To be fixed in https://github.com/dotnet/runtime/pull/77465
const bool tier0opts = !opts.compDbgCode && !opts.jitFlags->IsSet(JitFlags::JIT_FLAG_MIN_OPT);
if (!tier0opts)
{
return tree;
}
Expand Down
2 changes: 1 addition & 1 deletion src/coreclr/jit/importer.cpp
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Expand Up @@ -8232,7 +8232,7 @@ void Compiler::impImportBlockCode(BasicBlock* block)
op1->gtFlags |= (GTF_OVERFLOW | GTF_EXCEPT);
}

if (op1->gtGetOp1()->OperIsConst() && opts.OptimizationEnabled())
if (op1->gtGetOp1()->OperIsConst())
{
// Try and fold the introduced cast
op1 = gtFoldExprConst(op1);
Expand Down
3 changes: 1 addition & 2 deletions src/coreclr/jit/jit.h
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Expand Up @@ -701,7 +701,6 @@ class Histogram
#define CLFLG_QMARK 0x00080
#define CLFLG_TREETRANS 0x00100
#define CLFLG_INLINING 0x00200
#define CLFLG_CONSTANTFOLD 0x00800

#if FEATURE_STRUCTPROMOTE
#define CLFLG_STRUCTPROMOTE 0x00400
Expand All @@ -717,7 +716,7 @@ class Histogram

#define CLFLG_MAXOPT \
(CLFLG_CSE | CLFLG_REGVAR | CLFLG_RNGCHKOPT | CLFLG_DEADASGN | CLFLG_CODEMOTION | CLFLG_QMARK | CLFLG_TREETRANS | \
CLFLG_INLINING | CLFLG_STRUCTPROMOTE | CLFLG_CONSTANTFOLD)
CLFLG_INLINING | CLFLG_STRUCTPROMOTE)

#define CLFLG_MINOPT (CLFLG_TREETRANS)

Expand Down
28 changes: 21 additions & 7 deletions src/coreclr/jit/morph.cpp
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Expand Up @@ -8404,6 +8404,11 @@ GenTreeOp* Compiler::fgMorphCommutative(GenTreeOp* tree)
assert(varTypeIsIntegralOrI(tree->TypeGet()));
assert(tree->OperIs(GT_ADD, GT_MUL, GT_OR, GT_AND, GT_XOR));

if (opts.OptimizationDisabled())
{
return nullptr;
}

// op1 can be GT_COMMA, in this case we're going to fold
// "(op (COMMA(... (op X C1))) C2)" to "(COMMA(... (op X C3)))"
GenTree* op1 = tree->gtGetOp1()->gtEffectiveVal(true);
Expand Down Expand Up @@ -8836,7 +8841,7 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
// then don't morph to a helper call - it can be done faster inline using idiv.

noway_assert(op2);
if ((typ == TYP_LONG) && opts.OptEnabled(CLFLG_CONSTANTFOLD))
if ((typ == TYP_LONG) && opts.OptimizationEnabled())
{
if (op2->OperIs(GT_CNS_NATIVELONG) && op2->AsIntConCommon()->LngValue() >= 2 &&
op2->AsIntConCommon()->LngValue() <= 0x3fffffff)
Expand Down Expand Up @@ -8961,7 +8966,10 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA

GenTree* oldTree = tree;

tree = gtFoldExpr(tree);
if (opts.OptimizationEnabled())
{
tree = gtFoldExpr(tree);
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For the gtFold... seems like we should have a consistent pattern we use -- either the caller or the callee should check if optimizations are enabled, but not both?

Maybe this is covered in your opt levels PR?

}

// Were we able to fold it ?
// Note that gtFoldExpr may return a non-leaf even if successful
Expand Down Expand Up @@ -9398,8 +9406,11 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
qmarkOp2 = oldTree->AsOp()->gtOp2->AsOp()->gtOp2;
}

// Try to fold it, maybe we get lucky,
tree = gtFoldExpr(tree);
if (opts.OptimizationEnabled())
{
// Try to fold it, maybe we get lucky,
tree = gtFoldExpr(tree);
}

if (oldTree != tree)
{
Expand Down Expand Up @@ -9769,7 +9780,7 @@ GenTree* Compiler::fgMorphSmpOp(GenTree* tree, MorphAddrContext* mac, bool* optA
}

/* Any constant cases should have been folded earlier */
noway_assert(!op1->OperIsConst() || !opts.OptEnabled(CLFLG_CONSTANTFOLD) || optValnumCSE_phase);
noway_assert(!op1->OperIsConst() || opts.OptimizationDisabled() || optValnumCSE_phase);
break;

case GT_CKFINITE:
Expand Down Expand Up @@ -12769,8 +12780,11 @@ GenTree* Compiler::fgMorphTree(GenTree* tree, MorphAddrContext* mac)
tree->gtFlags |= tree->AsConditional()->gtOp1->gtFlags & GTF_ALL_EFFECT;
tree->gtFlags |= tree->AsConditional()->gtOp2->gtFlags & GTF_ALL_EFFECT;

// Try to fold away any constants etc.
tree = gtFoldExpr(tree);
if (opts.OptimizationEnabled())
{
// Try to fold away any constants etc.
tree = gtFoldExpr(tree);
}

break;

Expand Down