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[clang][bytecode] Implement the constexpr built-in abs function. #112459

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[clang][bytecode] Implement the constexpr built-in abs function. #112459

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dfa1585
implement constexpr builtin {l}abs
c8ef Oct 16, 2024
52e1d07
Update InterpBuiltin.cpp
c8ef Oct 16, 2024
2271935
Update ExprConstant.cpp
c8ef Oct 16, 2024
5f45e1f
Update InterpBuiltin.cpp
c8ef Oct 16, 2024
05b6cd4
Update ExprConstant.cpp
c8ef Oct 16, 2024
12e545f
Update ExprConstant.cpp
c8ef Oct 16, 2024
0adef10
Update ExprConstant.cpp
c8ef Oct 16, 2024
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1 change: 1 addition & 0 deletions clang/include/clang/Basic/Builtins.td
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Original file line number Diff line number Diff line change
Expand Up @@ -2714,6 +2714,7 @@ def Abs : IntMathTemplate, LibBuiltin<"stdlib.h"> {
let Attributes = [NoThrow, Const];
let Prototype = "T(T)";
let AddBuiltinPrefixedAlias = 1;
let OnlyBuiltinPrefixedAliasIsConstexpr = 1;
}

def Calloc : LibBuiltin<"stdlib.h"> {
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18 changes: 18 additions & 0 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Expand Up @@ -563,6 +563,17 @@ static bool interp__builtin_fabs(InterpState &S, CodePtr OpPC,
return true;
}

static bool interp__builtin_abs(InterpState &S, CodePtr OpPC,
const InterpFrame *Frame, const Function *Func,
const CallExpr *Call) {
PrimType ArgT = *S.getContext().classify(Call->getArg(0)->getType());
APSInt Val = peekToAPSInt(S.Stk, ArgT);
if (Val.isNegative())
Val.negate();
pushInteger(S, Val, Call->getType());
return true;
}

static bool interp__builtin_popcount(InterpState &S, CodePtr OpPC,
const InterpFrame *Frame,
const Function *Func,
Expand Down Expand Up @@ -1808,6 +1819,13 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
return false;
break;

case Builtin::BI__builtin_abs:
case Builtin::BI__builtin_labs:
case Builtin::BI__builtin_llabs:
if (!interp__builtin_abs(S, OpPC, Frame, F, Call))
return false;
break;

case Builtin::BI__builtin_popcount:
case Builtin::BI__builtin_popcountl:
case Builtin::BI__builtin_popcountll:
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13 changes: 13 additions & 0 deletions clang/lib/AST/ExprConstant.cpp
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Expand Up @@ -13055,6 +13055,19 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
return Success(Val.popcount() % 2, E);
}

case Builtin::BI__builtin_abs:
case Builtin::BI__builtin_labs:
case Builtin::BI__builtin_llabs: {
APSInt Val;
if (!EvaluateInteger(E->getArg(0), Val, Info))
return false;
if (Val == APSInt(APSInt::getSignedMinValue(Val.getBitWidth()), false))
return false;
if (Val.isNegative())
Val.negate();
return Success(Val, E);
}

case Builtin::BI__builtin_popcount:
case Builtin::BI__builtin_popcountl:
case Builtin::BI__builtin_popcountll:
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9 changes: 9 additions & 0 deletions clang/test/AST/ByteCode/builtin-functions.cpp
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Expand Up @@ -265,6 +265,15 @@ namespace fpclassify {
char classify_subnorm [__builtin_fpclassify(-1, -1, -1, +1, -1, 1.0e-38f)];
}

namespace abs {
static_assert(__builtin_abs(14) == 14, "");
static_assert(__builtin_labs(14L) == 14L, "");
static_assert(__builtin_llabs(14LL) == 14LL, "");
static_assert(__builtin_abs(-14) == 14, "");
static_assert(__builtin_labs(-14L) == 14L, "");
static_assert(__builtin_llabs(-14LL) == 14LL, "");
} // namespace abs

namespace fabs {
static_assert(__builtin_fabs(-14.0) == 14.0, "");
}
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