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[TableGen] Simplify generated code for isSubclass #117351

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Merged
merged 6 commits into from
Nov 28, 2024
Merged

[TableGen] Simplify generated code for isSubclass #117351

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86cadae
[TableGen] Simplify generated code for isSubclass
jayfoad Nov 22, 2024
eafb850
clang-format
jayfoad Nov 25, 2024
6d59a91
Use binary_search
jayfoad Nov 25, 2024
912547b
Remove casts to unsigned
jayfoad Nov 25, 2024
3e5035b
Use bit table lookup
jayfoad Nov 27, 2024
8052b48
clang-format
jayfoad Nov 27, 2024
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50 changes: 18 additions & 32 deletions llvm/utils/TableGen/AsmMatcherEmitter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2541,7 +2541,6 @@ static void emitIsSubclass(CodeGenTarget &Target,
OS << " if (A == B)\n";
OS << " return true;\n\n";

bool EmittedSwitch = false;
for (const auto &A : Infos) {
std::vector<StringRef> SuperClasses;
if (A.IsOptional)
Expand All @@ -2551,42 +2550,29 @@ static void emitIsSubclass(CodeGenTarget &Target,
SuperClasses.push_back(B.Name);
}

if (SuperClasses.empty())
if (SuperClasses.empty()) {
OS << " static constexpr ArrayRef<uint16_t> " << A.Name << "_SuperClasses;\n";
continue;

// If this is the first SuperClass, emit the switch header.
if (!EmittedSwitch) {
OS << " switch (A) {\n";
OS << " default:\n";
OS << " return false;\n";
EmittedSwitch = true;
}

OS << "\n case " << A.Name << ":\n";

if (SuperClasses.size() == 1) {
OS << " return B == " << SuperClasses.back() << ";\n";
continue;
}

if (!SuperClasses.empty()) {
OS << " switch (B) {\n";
OS << " default: return false;\n";
for (StringRef SC : SuperClasses)
OS << " case " << SC << ": return true;\n";
OS << " }\n";
} else {
// No case statement to emit
OS << " return false;\n";
}
OS << " static constexpr uint16_t " << A.Name << "_SuperClasses[] = {";
ListSeparator LS;
for (auto &SC : SuperClasses)
OS << LS << SC;
OS << "};\n";
}
OS << "\n";

// If there were case statements emitted into the string stream write the
// default.
if (EmittedSwitch)
OS << " }\n";
else
OS << " return false;\n";
OS << " static constexpr ArrayRef<uint16_t> SuperClassTable[] = {\n";
OS << " {}, // InvalidMatchClass\n";
OS << " {}, // OptionalMatchClass\n";
for (const auto &A : Infos)
OS << " " << A.Name << "_SuperClasses,\n";
OS << " };\n\n";

OS << " ArrayRef<uint16_t> SuperClasses = SuperClassTable[(unsigned)A];\n";
OS << " const uint16_t *It = lower_bound(SuperClasses, (unsigned)B);\n";
OS << " return It != SuperClasses.end() && *It == (unsigned)B;\n";

OS << "}\n\n";
}
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