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An implementation of __builtin__fpclassify the way Chris Lattner described by Jörg Blank. 

llvm-svn: 105936
This commit is contained in:
Benjamin Kramer 2010-06-14 10:30:41 +00:00
parent ba1f1fcae5
commit 7039fcbc5d
1 changed files with 58 additions and 0 deletions
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58
clang/lib/CodeGen/CGBuiltin.cpp
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@ -395,6 +395,64 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
V = Builder.CreateAnd(Eq, IsNotInf, "and");
return RValue::get(Builder.CreateZExt(V, ConvertType(E->getType())));
}
case Builtin::BI__builtin_fpclassify: {
Value *V = EmitScalarExpr(E->getArg(5));
const llvm::Type *Ty = ConvertType(E->getArg(5)->getType());
// Create Result
BasicBlock *Begin = Builder.GetInsertBlock();
BasicBlock *End = createBasicBlock("fpclassify_end", this->CurFn);
Builder.SetInsertPoint(End);
PHINode *Result =
Builder.CreatePHI(ConvertType(E->getArg(0)->getType()),
"fpclassify_result");
// if (V==0) return FP_ZERO
Builder.SetInsertPoint(Begin);
Value *IsZero = Builder.CreateFCmpOEQ(V, Constant::getNullValue(Ty),
"iszero");
Value *ZeroLiteral = EmitScalarExpr(E->getArg(4));
BasicBlock *NotZero = createBasicBlock("fpclassify_not_zero", this->CurFn);
Builder.CreateCondBr(IsZero, End, NotZero);
Result->addIncoming(ZeroLiteral, Begin);
// if (V != V) return FP_NAN
Builder.SetInsertPoint(NotZero);
Value *IsNan = Builder.CreateFCmpUNO(V, V, "cmp");
Value *NanLiteral = EmitScalarExpr(E->getArg(0));
BasicBlock *NotNan = createBasicBlock("fpclassify_not_nan", this->CurFn);
Builder.CreateCondBr(IsNan, End, NotNan);
Result->addIncoming(NanLiteral, NotZero);
// if (fabs(V) == infinity) return FP_INFINITY
Builder.SetInsertPoint(NotNan);
Value *VAbs = EmitFAbs(*this, V, E->getArg(5)->getType());
Value *IsInf =
Builder.CreateFCmpOEQ(VAbs, ConstantFP::getInfinity(V->getType()),
"isinf");
Value *InfLiteral = EmitScalarExpr(E->getArg(1));
BasicBlock *NotInf = createBasicBlock("fpclassify_not_inf", this->CurFn);
Builder.CreateCondBr(IsInf, End, NotInf);
Result->addIncoming(InfLiteral, NotNan);
// if (fabs(V) >= MIN_NORMAL) return FP_NORMAL else FP_SUBNORMAL
Builder.SetInsertPoint(NotInf);
APFloat Smallest = APFloat::getSmallestNormalized(
getContext().getFloatTypeSemantics(E->getArg(5)->getType()));
Value *IsNormal =
Builder.CreateFCmpUGE(VAbs, ConstantFP::get(V->getContext(), Smallest),
"isnormal");
Value *NormalResult =
Builder.CreateSelect(IsNormal, EmitScalarExpr(E->getArg(2)),
EmitScalarExpr(E->getArg(3)));
Builder.CreateBr(End);
Result->addIncoming(NormalResult, NotInf);
// return Result
Builder.SetInsertPoint(End);
return RValue::get(Result);
}
case Builtin::BIalloca:
case Builtin::BI__builtin_alloca: {