1 //===--- CGExprComplex.cpp - Emit LLVM Code for Complex Exprs -------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This contains code to emit Expr nodes with complex types as LLVM code.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CodeGenFunction.h"
15 #include "CodeGenModule.h"
16 #include "clang/AST/AST.h"
17 #include "llvm/Constants.h"
18 #include "llvm/Function.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/Support/Compiler.h"
21 using namespace clang;
22 using namespace CodeGen;
23 
24 //===----------------------------------------------------------------------===//
25 //                        Complex Expression Emitter
26 //===----------------------------------------------------------------------===//
27 
28 typedef CodeGenFunction::ComplexPairTy ComplexPairTy;
29 
30 namespace  {
31 class VISIBILITY_HIDDEN ComplexExprEmitter
32   : public StmtVisitor<ComplexExprEmitter, ComplexPairTy> {
33   CodeGenFunction &CGF;
34   llvm::IRBuilder &Builder;
35 public:
36   ComplexExprEmitter(CodeGenFunction &cgf) : CGF(cgf), Builder(CGF.Builder) {
37   }
38 
39 
40   //===--------------------------------------------------------------------===//
41   //                               Utilities
42   //===--------------------------------------------------------------------===//
43 
44   /// EmitLoadOfLValue - Given an expression with complex type that represents a
45   /// value l-value, this method emits the address of the l-value, then loads
46   /// and returns the result.
47   ComplexPairTy EmitLoadOfLValue(const Expr *E) {
48     LValue LV = CGF.EmitLValue(E);
49     // FIXME: Volatile
50     return EmitLoadOfComplex(LV.getAddress(), false);
51   }
52 
53   /// EmitLoadOfComplex - Given a pointer to a complex value, emit code to load
54   /// the real and imaginary pieces.
55   ComplexPairTy EmitLoadOfComplex(llvm::Value *SrcPtr, bool isVolatile);
56 
57   /// EmitStoreOfComplex - Store the specified real/imag parts into the
58   /// specified value pointer.
59   void EmitStoreOfComplex(ComplexPairTy Val, llvm::Value *ResPtr, bool isVol);
60 
61   /// EmitComplexToComplexCast - Emit a cast from complex value Val to DestType.
62   ComplexPairTy EmitComplexToComplexCast(ComplexPairTy Val, QualType SrcType,
63                                          QualType DestType);
64 
65   //===--------------------------------------------------------------------===//
66   //                            Visitor Methods
67   //===--------------------------------------------------------------------===//
68 
69   ComplexPairTy VisitStmt(Stmt *S) {
70     S->dump(CGF.getContext().getSourceManager());
71     assert(0 && "Stmt can't have complex result type!");
72     return ComplexPairTy();
73   }
74   ComplexPairTy VisitExpr(Expr *S);
75   ComplexPairTy VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr());}
76   ComplexPairTy VisitImaginaryLiteral(const ImaginaryLiteral *IL);
77 
78   // l-values.
79   ComplexPairTy VisitDeclRefExpr(const Expr *E) { return EmitLoadOfLValue(E); }
80   ComplexPairTy VisitArraySubscriptExpr(Expr *E) { return EmitLoadOfLValue(E); }
81   ComplexPairTy VisitMemberExpr(const Expr *E) { return EmitLoadOfLValue(E); }
82 
83   // FIXME: CompoundLiteralExpr
84 
85   ComplexPairTy EmitCast(Expr *Op, QualType DestTy);
86   ComplexPairTy VisitImplicitCastExpr(ImplicitCastExpr *E) {
87     // Unlike for scalars, we don't have to worry about function->ptr demotion
88     // here.
89     return EmitCast(E->getSubExpr(), E->getType());
90   }
91   ComplexPairTy VisitCastExpr(CastExpr *E) {
92     return EmitCast(E->getSubExpr(), E->getType());
93   }
94   ComplexPairTy VisitCallExpr(const CallExpr *E);
95   ComplexPairTy VisitStmtExpr(const StmtExpr *E);
96   ComplexPairTy VisitOverloadExpr(const OverloadExpr *OE);
97 
98   // Operators.
99   ComplexPairTy VisitPrePostIncDec(const UnaryOperator *E,
100                                    bool isInc, bool isPre);
101   ComplexPairTy VisitUnaryPostDec(const UnaryOperator *E) {
102     return VisitPrePostIncDec(E, false, false);
103   }
104   ComplexPairTy VisitUnaryPostInc(const UnaryOperator *E) {
105     return VisitPrePostIncDec(E, true, false);
106   }
107   ComplexPairTy VisitUnaryPreDec(const UnaryOperator *E) {
108     return VisitPrePostIncDec(E, false, true);
109   }
110   ComplexPairTy VisitUnaryPreInc(const UnaryOperator *E) {
111     return VisitPrePostIncDec(E, true, true);
112   }
113   ComplexPairTy VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); }
114   ComplexPairTy VisitUnaryPlus     (const UnaryOperator *E) {
115     return Visit(E->getSubExpr());
116   }
117   ComplexPairTy VisitUnaryMinus    (const UnaryOperator *E);
118   ComplexPairTy VisitUnaryNot      (const UnaryOperator *E);
119   // LNot,SizeOf,AlignOf,Real,Imag never return complex.
120   ComplexPairTy VisitUnaryExtension(const UnaryOperator *E) {
121     return Visit(E->getSubExpr());
122   }
123   ComplexPairTy VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
124     return Visit(DAE->getExpr());
125   }
126 
127   struct BinOpInfo {
128     ComplexPairTy LHS;
129     ComplexPairTy RHS;
130     QualType Ty;  // Computation Type.
131   };
132 
133   BinOpInfo EmitBinOps(const BinaryOperator *E);
134   ComplexPairTy EmitCompoundAssign(const CompoundAssignOperator *E,
135                                    ComplexPairTy (ComplexExprEmitter::*Func)
136                                    (const BinOpInfo &));
137 
138   ComplexPairTy EmitBinAdd(const BinOpInfo &Op);
139   ComplexPairTy EmitBinSub(const BinOpInfo &Op);
140   ComplexPairTy EmitBinMul(const BinOpInfo &Op);
141   ComplexPairTy EmitBinDiv(const BinOpInfo &Op);
142 
143   ComplexPairTy VisitBinMul(const BinaryOperator *E) {
144     return EmitBinMul(EmitBinOps(E));
145   }
146   ComplexPairTy VisitBinAdd(const BinaryOperator *E) {
147     return EmitBinAdd(EmitBinOps(E));
148   }
149   ComplexPairTy VisitBinSub(const BinaryOperator *E) {
150     return EmitBinSub(EmitBinOps(E));
151   }
152   ComplexPairTy VisitBinDiv(const BinaryOperator *E) {
153     return EmitBinDiv(EmitBinOps(E));
154   }
155 
156   // Compound assignments.
157   ComplexPairTy VisitBinAddAssign(const CompoundAssignOperator *E) {
158     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinAdd);
159   }
160   ComplexPairTy VisitBinSubAssign(const CompoundAssignOperator *E) {
161     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinSub);
162   }
163   ComplexPairTy VisitBinMulAssign(const CompoundAssignOperator *E) {
164     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinMul);
165   }
166   ComplexPairTy VisitBinDivAssign(const CompoundAssignOperator *E) {
167     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinDiv);
168   }
169 
170   // GCC rejects rem/and/or/xor for integer complex.
171   // Logical and/or always return int, never complex.
172 
173   // No comparisons produce a complex result.
174   ComplexPairTy VisitBinAssign     (const BinaryOperator *E);
175   ComplexPairTy VisitBinComma      (const BinaryOperator *E);
176 
177 
178   ComplexPairTy VisitConditionalOperator(const ConditionalOperator *CO);
179   ComplexPairTy VisitChooseExpr(ChooseExpr *CE);
180 };
181 }  // end anonymous namespace.
182 
183 //===----------------------------------------------------------------------===//
184 //                                Utilities
185 //===----------------------------------------------------------------------===//
186 
187 /// EmitLoadOfComplex - Given an RValue reference for a complex, emit code to
188 /// load the real and imaginary pieces, returning them as Real/Imag.
189 ComplexPairTy ComplexExprEmitter::EmitLoadOfComplex(llvm::Value *SrcPtr,
190                                                     bool isVolatile) {
191   llvm::SmallString<64> Name(SrcPtr->getNameStart(),
192                              SrcPtr->getNameStart()+SrcPtr->getNameLen());
193 
194   Name += ".realp";
195   llvm::Value *RealPtr = Builder.CreateStructGEP(SrcPtr, 0, Name.c_str());
196 
197   Name.pop_back();  // .realp -> .real
198   llvm::Value *Real = Builder.CreateLoad(RealPtr, isVolatile, Name.c_str());
199 
200   Name.resize(Name.size()-4); // .real -> .imagp
201   Name += "imagp";
202 
203   llvm::Value *ImagPtr = Builder.CreateStructGEP(SrcPtr, 1, Name.c_str());
204 
205   Name.pop_back();  // .imagp -> .imag
206   llvm::Value *Imag = Builder.CreateLoad(ImagPtr, isVolatile, Name.c_str());
207   return ComplexPairTy(Real, Imag);
208 }
209 
210 /// EmitStoreOfComplex - Store the specified real/imag parts into the
211 /// specified value pointer.
212 void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val, llvm::Value *Ptr,
213                                             bool isVolatile) {
214   llvm::Value *RealPtr = Builder.CreateStructGEP(Ptr, 0, "real");
215   llvm::Value *ImagPtr = Builder.CreateStructGEP(Ptr, 1, "imag");
216 
217   Builder.CreateStore(Val.first, RealPtr, isVolatile);
218   Builder.CreateStore(Val.second, ImagPtr, isVolatile);
219 }
220 
221 
222 
223 //===----------------------------------------------------------------------===//
224 //                            Visitor Methods
225 //===----------------------------------------------------------------------===//
226 
227 ComplexPairTy ComplexExprEmitter::VisitExpr(Expr *E) {
228   CGF.WarnUnsupported(E, "complex expression");
229   const llvm::Type *EltTy =
230     CGF.ConvertType(E->getType()->getAsComplexType()->getElementType());
231   llvm::Value *U = llvm::UndefValue::get(EltTy);
232   return ComplexPairTy(U, U);
233 }
234 
235 ComplexPairTy ComplexExprEmitter::
236 VisitImaginaryLiteral(const ImaginaryLiteral *IL) {
237   llvm::Value *Imag = CGF.EmitScalarExpr(IL->getSubExpr());
238   return ComplexPairTy(llvm::Constant::getNullValue(Imag->getType()), Imag);
239 }
240 
241 
242 ComplexPairTy ComplexExprEmitter::VisitCallExpr(const CallExpr *E) {
243   return CGF.EmitCallExpr(E).getComplexVal();
244 }
245 
246 ComplexPairTy ComplexExprEmitter::VisitOverloadExpr(const OverloadExpr *E) {
247   return CGF.EmitCallExpr(E->getFn(), E->arg_begin(),
248                           E->getNumArgs(CGF.getContext())).getComplexVal();
249 }
250 
251 ComplexPairTy ComplexExprEmitter::VisitStmtExpr(const StmtExpr *E) {
252   return CGF.EmitCompoundStmt(*E->getSubStmt(), true).getComplexVal();
253 }
254 
255 /// EmitComplexToComplexCast - Emit a cast from complex value Val to DestType.
256 ComplexPairTy ComplexExprEmitter::EmitComplexToComplexCast(ComplexPairTy Val,
257                                                            QualType SrcType,
258                                                            QualType DestType) {
259   // Get the src/dest element type.
260   SrcType = cast<ComplexType>(SrcType.getCanonicalType())->getElementType();
261   DestType = cast<ComplexType>(DestType.getCanonicalType())->getElementType();
262 
263   // C99 6.3.1.6: When a value of complextype is converted to another
264   // complex type, both the real and imaginary parts followthe conversion
265   // rules for the corresponding real types.
266   Val.first = CGF.EmitScalarConversion(Val.first, SrcType, DestType);
267   Val.second = CGF.EmitScalarConversion(Val.second, SrcType, DestType);
268   return Val;
269 }
270 
271 ComplexPairTy ComplexExprEmitter::EmitCast(Expr *Op, QualType DestTy) {
272   // Two cases here: cast from (complex to complex) and (scalar to complex).
273   if (Op->getType()->isAnyComplexType())
274     return EmitComplexToComplexCast(Visit(Op), Op->getType(), DestTy);
275 
276   // C99 6.3.1.7: When a value of real type is converted to a complex type, the
277   // real part of the complex  result value is determined by the rules of
278   // conversion to the corresponding real type and the imaginary part of the
279   // complex result value is a positive zero or an unsigned zero.
280   llvm::Value *Elt = CGF.EmitScalarExpr(Op);
281 
282   // Convert the input element to the element type of the complex.
283   DestTy = cast<ComplexType>(DestTy.getCanonicalType())->getElementType();
284   Elt = CGF.EmitScalarConversion(Elt, Op->getType(), DestTy);
285 
286   // Return (realval, 0).
287   return ComplexPairTy(Elt, llvm::Constant::getNullValue(Elt->getType()));
288 }
289 
290 ComplexPairTy ComplexExprEmitter::VisitPrePostIncDec(const UnaryOperator *E,
291                                                      bool isInc, bool isPre) {
292   LValue LV = CGF.EmitLValue(E->getSubExpr());
293   // FIXME: Handle volatile!
294   ComplexPairTy InVal = EmitLoadOfComplex(LV.getAddress(), false);
295 
296   uint64_t AmountVal = isInc ? 1 : -1;
297 
298   llvm::Value *NextVal;
299   if (isa<llvm::IntegerType>(InVal.first->getType()))
300     NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal);
301   else if (InVal.first->getType() == llvm::Type::FloatTy)
302     // FIXME: Handle long double.
303     NextVal =
304       llvm::ConstantFP::get(InVal.first->getType(),
305                             llvm::APFloat(static_cast<float>(AmountVal)));
306   else {
307     // FIXME: Handle long double.
308     assert(InVal.first->getType() == llvm::Type::DoubleTy);
309     NextVal =
310       llvm::ConstantFP::get(InVal.first->getType(),
311                             llvm::APFloat(static_cast<double>(AmountVal)));
312   }
313 
314   // Add the inc/dec to the real part.
315   NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
316 
317   ComplexPairTy IncVal(NextVal, InVal.second);
318 
319   // Store the updated result through the lvalue.
320   EmitStoreOfComplex(IncVal, LV.getAddress(), false);  /* FIXME: Volatile */
321 
322   // If this is a postinc, return the value read from memory, otherwise use the
323   // updated value.
324   return isPre ? IncVal : InVal;
325 }
326 
327 ComplexPairTy ComplexExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
328   ComplexPairTy Op = Visit(E->getSubExpr());
329   llvm::Value *ResR = Builder.CreateNeg(Op.first,  "neg.r");
330   llvm::Value *ResI = Builder.CreateNeg(Op.second, "neg.i");
331   return ComplexPairTy(ResR, ResI);
332 }
333 
334 ComplexPairTy ComplexExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
335   // ~(a+ib) = a + i*-b
336   ComplexPairTy Op = Visit(E->getSubExpr());
337   llvm::Value *ResI = Builder.CreateNeg(Op.second, "conj.i");
338   return ComplexPairTy(Op.first, ResI);
339 }
340 
341 ComplexPairTy ComplexExprEmitter::EmitBinAdd(const BinOpInfo &Op) {
342   llvm::Value *ResR = Builder.CreateAdd(Op.LHS.first,  Op.RHS.first,  "add.r");
343   llvm::Value *ResI = Builder.CreateAdd(Op.LHS.second, Op.RHS.second, "add.i");
344   return ComplexPairTy(ResR, ResI);
345 }
346 
347 ComplexPairTy ComplexExprEmitter::EmitBinSub(const BinOpInfo &Op) {
348   llvm::Value *ResR = Builder.CreateSub(Op.LHS.first,  Op.RHS.first,  "sub.r");
349   llvm::Value *ResI = Builder.CreateSub(Op.LHS.second, Op.RHS.second, "sub.i");
350   return ComplexPairTy(ResR, ResI);
351 }
352 
353 
354 ComplexPairTy ComplexExprEmitter::EmitBinMul(const BinOpInfo &Op) {
355   llvm::Value *ResRl = Builder.CreateMul(Op.LHS.first, Op.RHS.first, "mul.rl");
356   llvm::Value *ResRr = Builder.CreateMul(Op.LHS.second, Op.RHS.second,"mul.rr");
357   llvm::Value *ResR  = Builder.CreateSub(ResRl, ResRr, "mul.r");
358 
359   llvm::Value *ResIl = Builder.CreateMul(Op.LHS.second, Op.RHS.first, "mul.il");
360   llvm::Value *ResIr = Builder.CreateMul(Op.LHS.first, Op.RHS.second, "mul.ir");
361   llvm::Value *ResI  = Builder.CreateAdd(ResIl, ResIr, "mul.i");
362   return ComplexPairTy(ResR, ResI);
363 }
364 
365 ComplexPairTy ComplexExprEmitter::EmitBinDiv(const BinOpInfo &Op) {
366   llvm::Value *LHSr = Op.LHS.first, *LHSi = Op.LHS.second;
367   llvm::Value *RHSr = Op.RHS.first, *RHSi = Op.RHS.second;
368 
369   // (a+ib) / (c+id) = ((ac+bd)/(cc+dd)) + i((bc-ad)/(cc+dd))
370   llvm::Value *Tmp1 = Builder.CreateMul(LHSr, RHSr, "tmp"); // a*c
371   llvm::Value *Tmp2 = Builder.CreateMul(LHSi, RHSi, "tmp"); // b*d
372   llvm::Value *Tmp3 = Builder.CreateAdd(Tmp1, Tmp2, "tmp"); // ac+bd
373 
374   llvm::Value *Tmp4 = Builder.CreateMul(RHSr, RHSr, "tmp"); // c*c
375   llvm::Value *Tmp5 = Builder.CreateMul(RHSi, RHSi, "tmp"); // d*d
376   llvm::Value *Tmp6 = Builder.CreateAdd(Tmp4, Tmp5, "tmp"); // cc+dd
377 
378   llvm::Value *Tmp7 = Builder.CreateMul(LHSi, RHSr, "tmp"); // b*c
379   llvm::Value *Tmp8 = Builder.CreateMul(LHSr, RHSi, "tmp"); // a*d
380   llvm::Value *Tmp9 = Builder.CreateSub(Tmp7, Tmp8, "tmp"); // bc-ad
381 
382   llvm::Value *DSTr, *DSTi;
383   if (Tmp3->getType()->isFloatingPoint()) {
384     DSTr = Builder.CreateFDiv(Tmp3, Tmp6, "tmp");
385     DSTi = Builder.CreateFDiv(Tmp9, Tmp6, "tmp");
386   } else {
387     if (Op.Ty->getAsComplexType()->getElementType()->isUnsignedIntegerType()) {
388       DSTr = Builder.CreateUDiv(Tmp3, Tmp6, "tmp");
389       DSTi = Builder.CreateUDiv(Tmp9, Tmp6, "tmp");
390     } else {
391       DSTr = Builder.CreateSDiv(Tmp3, Tmp6, "tmp");
392       DSTi = Builder.CreateSDiv(Tmp9, Tmp6, "tmp");
393     }
394   }
395 
396   return ComplexPairTy(DSTr, DSTi);
397 }
398 
399 ComplexExprEmitter::BinOpInfo
400 ComplexExprEmitter::EmitBinOps(const BinaryOperator *E) {
401   BinOpInfo Ops;
402   Ops.LHS = Visit(E->getLHS());
403   Ops.RHS = Visit(E->getRHS());
404   Ops.Ty = E->getType();
405   return Ops;
406 }
407 
408 
409 // Compound assignments.
410 ComplexPairTy ComplexExprEmitter::
411 EmitCompoundAssign(const CompoundAssignOperator *E,
412                    ComplexPairTy (ComplexExprEmitter::*Func)(const BinOpInfo&)){
413   QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType();
414 
415   // Load the LHS and RHS operands.
416   LValue LHSLV = CGF.EmitLValue(E->getLHS());
417 
418   BinOpInfo OpInfo;
419   OpInfo.Ty = E->getComputationType();
420 
421   // We know the LHS is a complex lvalue.
422   OpInfo.LHS = EmitLoadOfComplex(LHSLV.getAddress(), false);// FIXME: Volatile.
423   OpInfo.LHS = EmitComplexToComplexCast(OpInfo.LHS, LHSTy, OpInfo.Ty);
424 
425   // It is possible for the RHS to be complex or scalar.
426   OpInfo.RHS = EmitCast(E->getRHS(), OpInfo.Ty);
427 
428   // Expand the binary operator.
429   ComplexPairTy Result = (this->*Func)(OpInfo);
430 
431   // Truncate the result back to the LHS type.
432   Result = EmitComplexToComplexCast(Result, OpInfo.Ty, LHSTy);
433 
434   // Store the result value into the LHS lvalue.
435   EmitStoreOfComplex(Result, LHSLV.getAddress(), false); // FIXME: VOLATILE
436   return Result;
437 }
438 
439 ComplexPairTy ComplexExprEmitter::VisitBinAssign(const BinaryOperator *E) {
440   assert(E->getLHS()->getType().getCanonicalType() ==
441          E->getRHS()->getType().getCanonicalType() && "Invalid assignment");
442   // Emit the RHS.
443   ComplexPairTy Val = Visit(E->getRHS());
444 
445   // Compute the address to store into.
446   LValue LHS = CGF.EmitLValue(E->getLHS());
447 
448   // Store into it.
449   // FIXME: Volatility!
450   EmitStoreOfComplex(Val, LHS.getAddress(), false);
451   return Val;
452 }
453 
454 ComplexPairTy ComplexExprEmitter::VisitBinComma(const BinaryOperator *E) {
455   CGF.EmitStmt(E->getLHS());
456   return Visit(E->getRHS());
457 }
458 
459 ComplexPairTy ComplexExprEmitter::
460 VisitConditionalOperator(const ConditionalOperator *E) {
461   llvm::BasicBlock *LHSBlock = llvm::BasicBlock::Create("cond.?");
462   llvm::BasicBlock *RHSBlock = llvm::BasicBlock::Create("cond.:");
463   llvm::BasicBlock *ContBlock = llvm::BasicBlock::Create("cond.cont");
464 
465   llvm::Value *Cond = CGF.EvaluateExprAsBool(E->getCond());
466   Builder.CreateCondBr(Cond, LHSBlock, RHSBlock);
467 
468   CGF.EmitBlock(LHSBlock);
469 
470   // Handle the GNU extension for missing LHS.
471   assert(E->getLHS() && "Must have LHS for complex value");
472 
473   ComplexPairTy LHS = Visit(E->getLHS());
474   Builder.CreateBr(ContBlock);
475   LHSBlock = Builder.GetInsertBlock();
476 
477   CGF.EmitBlock(RHSBlock);
478 
479   ComplexPairTy RHS = Visit(E->getRHS());
480   Builder.CreateBr(ContBlock);
481   RHSBlock = Builder.GetInsertBlock();
482 
483   CGF.EmitBlock(ContBlock);
484 
485   // Create a PHI node for the real part.
486   llvm::PHINode *RealPN = Builder.CreatePHI(LHS.first->getType(), "cond.r");
487   RealPN->reserveOperandSpace(2);
488   RealPN->addIncoming(LHS.first, LHSBlock);
489   RealPN->addIncoming(RHS.first, RHSBlock);
490 
491   // Create a PHI node for the imaginary part.
492   llvm::PHINode *ImagPN = Builder.CreatePHI(LHS.first->getType(), "cond.i");
493   ImagPN->reserveOperandSpace(2);
494   ImagPN->addIncoming(LHS.second, LHSBlock);
495   ImagPN->addIncoming(RHS.second, RHSBlock);
496 
497   return ComplexPairTy(RealPN, ImagPN);
498 }
499 
500 ComplexPairTy ComplexExprEmitter::VisitChooseExpr(ChooseExpr *E) {
501   // Emit the LHS or RHS as appropriate.
502   return Visit(E->isConditionTrue(CGF.getContext()) ? E->getLHS() :E->getRHS());
503 }
504 
505 //===----------------------------------------------------------------------===//
506 //                         Entry Point into this File
507 //===----------------------------------------------------------------------===//
508 
509 /// EmitComplexExpr - Emit the computation of the specified expression of
510 /// complex type, ignoring the result.
511 ComplexPairTy CodeGenFunction::EmitComplexExpr(const Expr *E) {
512   assert(E && E->getType()->isAnyComplexType() &&
513          "Invalid complex expression to emit");
514 
515   return ComplexExprEmitter(*this).Visit(const_cast<Expr*>(E));
516 }
517 
518 /// EmitComplexExprIntoAddr - Emit the computation of the specified expression
519 /// of complex type, storing into the specified Value*.
520 void CodeGenFunction::EmitComplexExprIntoAddr(const Expr *E,
521                                               llvm::Value *DestAddr,
522                                               bool DestIsVolatile) {
523   assert(E && E->getType()->isAnyComplexType() &&
524          "Invalid complex expression to emit");
525   ComplexExprEmitter Emitter(*this);
526   ComplexPairTy Val = Emitter.Visit(const_cast<Expr*>(E));
527   Emitter.EmitStoreOfComplex(Val, DestAddr, DestIsVolatile);
528 }
529 
530 /// LoadComplexFromAddr - Load a complex number from the specified address.
531 ComplexPairTy CodeGenFunction::LoadComplexFromAddr(llvm::Value *SrcAddr,
532                                                    bool SrcIsVolatile) {
533   return ComplexExprEmitter(*this).EmitLoadOfComplex(SrcAddr, SrcIsVolatile);
534 }
535