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[clang][bytecode] Add callback mechanism to handle constexpr for unary integer ops #160280

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Merged
RKSimon merged 3 commits into from
Sep 23, 2025
Merged

[clang][bytecode] Add callback mechanism to handle constexpr for unary integer ops #160280

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[clang][byte] Add callback mechanism to handle constexpr for unary in…
RKSimon Sep 23, 2025
b587ab6
Split asserts
RKSimon Sep 23, 2025
bd7818f
Merge branch 'main' into bytecode-constexpr-unary-op-callback
RKSimon Sep 23, 2025
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53 changes: 25 additions & 28 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1380,32 +1380,6 @@ static bool interp__builtin_ia32_bzhi(InterpState &S, CodePtr OpPC,
return true;
}

static bool interp__builtin_ia32_lzcnt(InterpState &S, CodePtr OpPC,
const InterpFrame *Frame,
const CallExpr *Call) {
QualType CallType = Call->getType();
if (!CallType->isIntegerType() ||
!Call->getArg(0)->getType()->isIntegerType())
return false;

APSInt Val = popToAPSInt(S, Call->getArg(0));
pushInteger(S, Val.countLeadingZeros(), CallType);
return true;
}

static bool interp__builtin_ia32_tzcnt(InterpState &S, CodePtr OpPC,
const InterpFrame *Frame,
const CallExpr *Call) {
QualType CallType = Call->getType();
if (!CallType->isIntegerType() ||
!Call->getArg(0)->getType()->isIntegerType())
return false;

APSInt Val = popToAPSInt(S, Call->getArg(0));
pushInteger(S, Val.countTrailingZeros(), CallType);
return true;
}

static bool interp__builtin_ia32_pdep(InterpState &S, CodePtr OpPC,
const InterpFrame *Frame,
const CallExpr *Call) {
Expand Down Expand Up @@ -2551,6 +2525,23 @@ static bool interp__builtin_is_within_lifetime(InterpState &S, CodePtr OpPC,
return true;
}

static bool interp__builtin_elementwise_int_unaryop(
InterpState &S, CodePtr OpPC, const CallExpr *Call,
llvm::function_ref<APInt(const APSInt &)> Fn) {
assert(Call->getType()->isIntegerType() && Call->getNumArgs() == 1);
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@tbaederr tbaederr Sep 23, 2025

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This should be two separate asserts so we know what the problem is if it fails


// Single integer case.
if (!Call->getArg(0)->getType()->isVectorType()) {
APSInt Src = popToAPSInt(S, Call->getArg(0));
APInt Result = Fn(Src);
pushInteger(S, APSInt(std::move(Result), !Src.isSigned()), Call->getType());
return true;
}

// TODO: Add vector integer handling.
return false;
}

static bool interp__builtin_elementwise_int_binop(
InterpState &S, CodePtr OpPC, const CallExpr *Call,
llvm::function_ref<APInt(const APSInt &, const APSInt &)> Fn) {
Expand Down Expand Up @@ -3283,12 +3274,18 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
case clang::X86::BI__builtin_ia32_lzcnt_u16:
case clang::X86::BI__builtin_ia32_lzcnt_u32:
case clang::X86::BI__builtin_ia32_lzcnt_u64:
return interp__builtin_ia32_lzcnt(S, OpPC, Frame, Call);
return interp__builtin_elementwise_int_unaryop(
S, OpPC, Call, [](const APSInt &Src) {
return APInt(Src.getBitWidth(), Src.countLeadingZeros());
});

case clang::X86::BI__builtin_ia32_tzcnt_u16:
case clang::X86::BI__builtin_ia32_tzcnt_u32:
case clang::X86::BI__builtin_ia32_tzcnt_u64:
return interp__builtin_ia32_tzcnt(S, OpPC, Frame, Call);
return interp__builtin_elementwise_int_unaryop(
S, OpPC, Call, [](const APSInt &Src) {
return APInt(Src.getBitWidth(), Src.countTrailingZeros());
});

case clang::X86::BI__builtin_ia32_pdep_si:
case clang::X86::BI__builtin_ia32_pdep_di:
Expand Down
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