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/ASTContext.h"
17 #include "clang/AST/StmtVisitor.h"
18 #include "llvm/Constants.h"
19 #include "llvm/Function.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/Support/Compiler.h"
22 using namespace clang;
23 using namespace CodeGen;
24 
25 //===----------------------------------------------------------------------===//
26 //                        Complex Expression Emitter
27 //===----------------------------------------------------------------------===//
28 
29 typedef CodeGenFunction::ComplexPairTy ComplexPairTy;
30 
31 namespace  {
32 class VISIBILITY_HIDDEN ComplexExprEmitter
33   : public StmtVisitor<ComplexExprEmitter, ComplexPairTy> {
34   CodeGenFunction &CGF;
35   CGBuilderTy &Builder;
36   // True is we should ignore the value of a
37   bool IgnoreReal;
38   bool IgnoreImag;
39   // True if we should ignore the value of a=b
40   bool IgnoreRealAssign;
41   bool IgnoreImagAssign;
42 public:
43   ComplexExprEmitter(CodeGenFunction &cgf, bool ir=false, bool ii=false,
44                      bool irn=false, bool iin=false)
45     : CGF(cgf), Builder(CGF.Builder), IgnoreReal(ir), IgnoreImag(ii),
46     IgnoreRealAssign(irn), IgnoreImagAssign(iin) {
47   }
48 
49 
50   //===--------------------------------------------------------------------===//
51   //                               Utilities
52   //===--------------------------------------------------------------------===//
53 
54   bool TestAndClearIgnoreReal() {
55     bool I = IgnoreReal;
56     IgnoreReal = false;
57     return I;
58   }
59   bool TestAndClearIgnoreImag() {
60     bool I = IgnoreImag;
61     IgnoreImag = false;
62     return I;
63   }
64   bool TestAndClearIgnoreRealAssign() {
65     bool I = IgnoreRealAssign;
66     IgnoreRealAssign = false;
67     return I;
68   }
69   bool TestAndClearIgnoreImagAssign() {
70     bool I = IgnoreImagAssign;
71     IgnoreImagAssign = false;
72     return I;
73   }
74 
75   /// EmitLoadOfLValue - Given an expression with complex type that represents a
76   /// value l-value, this method emits the address of the l-value, then loads
77   /// and returns the result.
78   ComplexPairTy EmitLoadOfLValue(const Expr *E) {
79     LValue LV = CGF.EmitLValue(E);
80     return EmitLoadOfComplex(LV.getAddress(), LV.isVolatileQualified());
81   }
82 
83   /// EmitLoadOfComplex - Given a pointer to a complex value, emit code to load
84   /// the real and imaginary pieces.
85   ComplexPairTy EmitLoadOfComplex(llvm::Value *SrcPtr, bool isVolatile);
86 
87   /// EmitStoreOfComplex - Store the specified real/imag parts into the
88   /// specified value pointer.
89   void EmitStoreOfComplex(ComplexPairTy Val, llvm::Value *ResPtr, bool isVol);
90 
91   /// EmitComplexToComplexCast - Emit a cast from complex value Val to DestType.
92   ComplexPairTy EmitComplexToComplexCast(ComplexPairTy Val, QualType SrcType,
93                                          QualType DestType);
94 
95   //===--------------------------------------------------------------------===//
96   //                            Visitor Methods
97   //===--------------------------------------------------------------------===//
98 
99   ComplexPairTy VisitStmt(Stmt *S) {
100     S->dump(CGF.getContext().getSourceManager());
101     assert(0 && "Stmt can't have complex result type!");
102     return ComplexPairTy();
103   }
104   ComplexPairTy VisitExpr(Expr *S);
105   ComplexPairTy VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr());}
106   ComplexPairTy VisitImaginaryLiteral(const ImaginaryLiteral *IL);
107 
108   // l-values.
109   ComplexPairTy VisitDeclRefExpr(const Expr *E) { return EmitLoadOfLValue(E); }
110   ComplexPairTy VisitArraySubscriptExpr(Expr *E) { return EmitLoadOfLValue(E); }
111   ComplexPairTy VisitMemberExpr(const Expr *E) { return EmitLoadOfLValue(E); }
112 
113   // FIXME: CompoundLiteralExpr
114 
115   ComplexPairTy EmitCast(Expr *Op, QualType DestTy);
116   ComplexPairTy VisitImplicitCastExpr(ImplicitCastExpr *E) {
117     // Unlike for scalars, we don't have to worry about function->ptr demotion
118     // here.
119     return EmitCast(E->getSubExpr(), E->getType());
120   }
121   ComplexPairTy VisitCastExpr(CastExpr *E) {
122     return EmitCast(E->getSubExpr(), E->getType());
123   }
124   ComplexPairTy VisitCallExpr(const CallExpr *E);
125   ComplexPairTy VisitStmtExpr(const StmtExpr *E);
126 
127   // Operators.
128   ComplexPairTy VisitPrePostIncDec(const UnaryOperator *E,
129                                    bool isInc, bool isPre);
130   ComplexPairTy VisitUnaryPostDec(const UnaryOperator *E) {
131     return VisitPrePostIncDec(E, false, false);
132   }
133   ComplexPairTy VisitUnaryPostInc(const UnaryOperator *E) {
134     return VisitPrePostIncDec(E, true, false);
135   }
136   ComplexPairTy VisitUnaryPreDec(const UnaryOperator *E) {
137     return VisitPrePostIncDec(E, false, true);
138   }
139   ComplexPairTy VisitUnaryPreInc(const UnaryOperator *E) {
140     return VisitPrePostIncDec(E, true, true);
141   }
142   ComplexPairTy VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); }
143   ComplexPairTy VisitUnaryPlus     (const UnaryOperator *E) {
144     TestAndClearIgnoreReal();
145     TestAndClearIgnoreImag();
146     TestAndClearIgnoreRealAssign();
147     TestAndClearIgnoreImagAssign();
148     return Visit(E->getSubExpr());
149   }
150   ComplexPairTy VisitUnaryMinus    (const UnaryOperator *E);
151   ComplexPairTy VisitUnaryNot      (const UnaryOperator *E);
152   // LNot,Real,Imag never return complex.
153   ComplexPairTy VisitUnaryExtension(const UnaryOperator *E) {
154     return Visit(E->getSubExpr());
155   }
156   ComplexPairTy VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
157     return Visit(DAE->getExpr());
158   }
159   ComplexPairTy VisitCXXZeroInitValueExpr(CXXZeroInitValueExpr *E) {
160     assert(E->getType()->isAnyComplexType() && "Expected complex type!");
161     QualType Elem = E->getType()->getAsComplexType()->getElementType();
162     llvm::Constant *Null = llvm::Constant::getNullValue(CGF.ConvertType(Elem));
163     return ComplexPairTy(Null, Null);
164   }
165   ComplexPairTy VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
166     assert(E->getType()->isAnyComplexType() && "Expected complex type!");
167     QualType Elem = E->getType()->getAsComplexType()->getElementType();
168     llvm::Constant *Null = llvm::Constant::getNullValue(CGF.ConvertType(Elem));
169     return ComplexPairTy(Null, Null);
170   }
171 
172   struct BinOpInfo {
173     ComplexPairTy LHS;
174     ComplexPairTy RHS;
175     QualType Ty;  // Computation Type.
176   };
177 
178   BinOpInfo EmitBinOps(const BinaryOperator *E);
179   ComplexPairTy EmitCompoundAssign(const CompoundAssignOperator *E,
180                                    ComplexPairTy (ComplexExprEmitter::*Func)
181                                    (const BinOpInfo &));
182 
183   ComplexPairTy EmitBinAdd(const BinOpInfo &Op);
184   ComplexPairTy EmitBinSub(const BinOpInfo &Op);
185   ComplexPairTy EmitBinMul(const BinOpInfo &Op);
186   ComplexPairTy EmitBinDiv(const BinOpInfo &Op);
187 
188   ComplexPairTy VisitBinMul(const BinaryOperator *E) {
189     return EmitBinMul(EmitBinOps(E));
190   }
191   ComplexPairTy VisitBinAdd(const BinaryOperator *E) {
192     return EmitBinAdd(EmitBinOps(E));
193   }
194   ComplexPairTy VisitBinSub(const BinaryOperator *E) {
195     return EmitBinSub(EmitBinOps(E));
196   }
197   ComplexPairTy VisitBinDiv(const BinaryOperator *E) {
198     return EmitBinDiv(EmitBinOps(E));
199   }
200 
201   // Compound assignments.
202   ComplexPairTy VisitBinAddAssign(const CompoundAssignOperator *E) {
203     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinAdd);
204   }
205   ComplexPairTy VisitBinSubAssign(const CompoundAssignOperator *E) {
206     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinSub);
207   }
208   ComplexPairTy VisitBinMulAssign(const CompoundAssignOperator *E) {
209     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinMul);
210   }
211   ComplexPairTy VisitBinDivAssign(const CompoundAssignOperator *E) {
212     return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinDiv);
213   }
214 
215   // GCC rejects rem/and/or/xor for integer complex.
216   // Logical and/or always return int, never complex.
217 
218   // No comparisons produce a complex result.
219   ComplexPairTy VisitBinAssign     (const BinaryOperator *E);
220   ComplexPairTy VisitBinComma      (const BinaryOperator *E);
221 
222 
223   ComplexPairTy VisitConditionalOperator(const ConditionalOperator *CO);
224   ComplexPairTy VisitChooseExpr(ChooseExpr *CE);
225 
226   ComplexPairTy VisitInitListExpr(InitListExpr *E);
227 
228   ComplexPairTy VisitVAArgExpr(VAArgExpr *E);
229 };
230 }  // end anonymous namespace.
231 
232 //===----------------------------------------------------------------------===//
233 //                                Utilities
234 //===----------------------------------------------------------------------===//
235 
236 /// EmitLoadOfComplex - Given an RValue reference for a complex, emit code to
237 /// load the real and imaginary pieces, returning them as Real/Imag.
238 ComplexPairTy ComplexExprEmitter::EmitLoadOfComplex(llvm::Value *SrcPtr,
239                                                     bool isVolatile) {
240   llvm::SmallString<64> Name(SrcPtr->getNameStart(),
241                              SrcPtr->getNameStart()+SrcPtr->getNameLen());
242 
243   llvm::Value *Real=0, *Imag=0;
244 
245   if (!IgnoreReal) {
246     Name += ".realp";
247     llvm::Value *RealPtr = Builder.CreateStructGEP(SrcPtr, 0, Name.c_str());
248 
249     Name.pop_back();  // .realp -> .real
250     Real = Builder.CreateLoad(RealPtr, isVolatile, Name.c_str());
251     Name.resize(Name.size()-4); // .real -> .imagp
252   }
253 
254   if (!IgnoreImag) {
255     Name += "imagp";
256 
257     llvm::Value *ImagPtr = Builder.CreateStructGEP(SrcPtr, 1, Name.c_str());
258 
259     Name.pop_back();  // .imagp -> .imag
260     Imag = Builder.CreateLoad(ImagPtr, isVolatile, Name.c_str());
261   }
262   return ComplexPairTy(Real, Imag);
263 }
264 
265 /// EmitStoreOfComplex - Store the specified real/imag parts into the
266 /// specified value pointer.
267 void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val, llvm::Value *Ptr,
268                                             bool isVolatile) {
269   llvm::Value *RealPtr = Builder.CreateStructGEP(Ptr, 0, "real");
270   llvm::Value *ImagPtr = Builder.CreateStructGEP(Ptr, 1, "imag");
271 
272   Builder.CreateStore(Val.first, RealPtr, isVolatile);
273   Builder.CreateStore(Val.second, ImagPtr, isVolatile);
274 }
275 
276 
277 
278 //===----------------------------------------------------------------------===//
279 //                            Visitor Methods
280 //===----------------------------------------------------------------------===//
281 
282 ComplexPairTy ComplexExprEmitter::VisitExpr(Expr *E) {
283   CGF.ErrorUnsupported(E, "complex expression");
284   const llvm::Type *EltTy =
285     CGF.ConvertType(E->getType()->getAsComplexType()->getElementType());
286   llvm::Value *U = llvm::UndefValue::get(EltTy);
287   return ComplexPairTy(U, U);
288 }
289 
290 ComplexPairTy ComplexExprEmitter::
291 VisitImaginaryLiteral(const ImaginaryLiteral *IL) {
292   llvm::Value *Imag = CGF.EmitScalarExpr(IL->getSubExpr());
293   return ComplexPairTy(llvm::Constant::getNullValue(Imag->getType()), Imag);
294 }
295 
296 
297 ComplexPairTy ComplexExprEmitter::VisitCallExpr(const CallExpr *E) {
298   if (E->getCallReturnType()->isReferenceType())
299     return EmitLoadOfLValue(E);
300 
301   return CGF.EmitCallExpr(E).getComplexVal();
302 }
303 
304 ComplexPairTy ComplexExprEmitter::VisitStmtExpr(const StmtExpr *E) {
305   return CGF.EmitCompoundStmt(*E->getSubStmt(), true).getComplexVal();
306 }
307 
308 /// EmitComplexToComplexCast - Emit a cast from complex value Val to DestType.
309 ComplexPairTy ComplexExprEmitter::EmitComplexToComplexCast(ComplexPairTy Val,
310                                                            QualType SrcType,
311                                                            QualType DestType) {
312   // Get the src/dest element type.
313   SrcType = SrcType->getAsComplexType()->getElementType();
314   DestType = DestType->getAsComplexType()->getElementType();
315 
316   // C99 6.3.1.6: When a value of complex type is converted to another
317   // complex type, both the real and imaginary parts follow the conversion
318   // rules for the corresponding real types.
319   Val.first = CGF.EmitScalarConversion(Val.first, SrcType, DestType);
320   Val.second = CGF.EmitScalarConversion(Val.second, SrcType, DestType);
321   return Val;
322 }
323 
324 ComplexPairTy ComplexExprEmitter::EmitCast(Expr *Op, QualType DestTy) {
325   // Two cases here: cast from (complex to complex) and (scalar to complex).
326   if (Op->getType()->isAnyComplexType())
327     return EmitComplexToComplexCast(Visit(Op), Op->getType(), DestTy);
328 
329   // C99 6.3.1.7: When a value of real type is converted to a complex type, the
330   // real part of the complex result value is determined by the rules of
331   // conversion to the corresponding real type and the imaginary part of the
332   // complex result value is a positive zero or an unsigned zero.
333   llvm::Value *Elt = CGF.EmitScalarExpr(Op);
334 
335   // Convert the input element to the element type of the complex.
336   DestTy = DestTy->getAsComplexType()->getElementType();
337   Elt = CGF.EmitScalarConversion(Elt, Op->getType(), DestTy);
338 
339   // Return (realval, 0).
340   return ComplexPairTy(Elt, llvm::Constant::getNullValue(Elt->getType()));
341 }
342 
343 ComplexPairTy ComplexExprEmitter::VisitPrePostIncDec(const UnaryOperator *E,
344                                                      bool isInc, bool isPre) {
345   LValue LV = CGF.EmitLValue(E->getSubExpr());
346   ComplexPairTy InVal = EmitLoadOfComplex(LV.getAddress(), LV.isVolatileQualified());
347 
348   llvm::Value *NextVal;
349   if (isa<llvm::IntegerType>(InVal.first->getType())) {
350     uint64_t AmountVal = isInc ? 1 : -1;
351     NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
352   } else {
353     QualType ElemTy = E->getType()->getAsComplexType()->getElementType();
354     llvm::APFloat FVal(CGF.getContext().getFloatTypeSemantics(ElemTy), 1);
355     if (!isInc)
356       FVal.changeSign();
357     NextVal = llvm::ConstantFP::get(FVal);
358   }
359 
360   // Add the inc/dec to the real part.
361   NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
362 
363   ComplexPairTy IncVal(NextVal, InVal.second);
364 
365   // Store the updated result through the lvalue.
366   EmitStoreOfComplex(IncVal, LV.getAddress(), LV.isVolatileQualified());
367 
368   // If this is a postinc, return the value read from memory, otherwise use the
369   // updated value.
370   return isPre ? IncVal : InVal;
371 }
372 
373 ComplexPairTy ComplexExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
374   TestAndClearIgnoreReal();
375   TestAndClearIgnoreImag();
376   TestAndClearIgnoreRealAssign();
377   TestAndClearIgnoreImagAssign();
378   ComplexPairTy Op = Visit(E->getSubExpr());
379   llvm::Value *ResR = Builder.CreateNeg(Op.first,  "neg.r");
380   llvm::Value *ResI = Builder.CreateNeg(Op.second, "neg.i");
381   return ComplexPairTy(ResR, ResI);
382 }
383 
384 ComplexPairTy ComplexExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
385   TestAndClearIgnoreReal();
386   TestAndClearIgnoreImag();
387   TestAndClearIgnoreRealAssign();
388   TestAndClearIgnoreImagAssign();
389   // ~(a+ib) = a + i*-b
390   ComplexPairTy Op = Visit(E->getSubExpr());
391   llvm::Value *ResI = Builder.CreateNeg(Op.second, "conj.i");
392   return ComplexPairTy(Op.first, ResI);
393 }
394 
395 ComplexPairTy ComplexExprEmitter::EmitBinAdd(const BinOpInfo &Op) {
396   llvm::Value *ResR = Builder.CreateAdd(Op.LHS.first,  Op.RHS.first,  "add.r");
397   llvm::Value *ResI = Builder.CreateAdd(Op.LHS.second, Op.RHS.second, "add.i");
398   return ComplexPairTy(ResR, ResI);
399 }
400 
401 ComplexPairTy ComplexExprEmitter::EmitBinSub(const BinOpInfo &Op) {
402   llvm::Value *ResR = Builder.CreateSub(Op.LHS.first,  Op.RHS.first,  "sub.r");
403   llvm::Value *ResI = Builder.CreateSub(Op.LHS.second, Op.RHS.second, "sub.i");
404   return ComplexPairTy(ResR, ResI);
405 }
406 
407 
408 ComplexPairTy ComplexExprEmitter::EmitBinMul(const BinOpInfo &Op) {
409   llvm::Value *ResRl = Builder.CreateMul(Op.LHS.first, Op.RHS.first, "mul.rl");
410   llvm::Value *ResRr = Builder.CreateMul(Op.LHS.second, Op.RHS.second,"mul.rr");
411   llvm::Value *ResR  = Builder.CreateSub(ResRl, ResRr, "mul.r");
412 
413   llvm::Value *ResIl = Builder.CreateMul(Op.LHS.second, Op.RHS.first, "mul.il");
414   llvm::Value *ResIr = Builder.CreateMul(Op.LHS.first, Op.RHS.second, "mul.ir");
415   llvm::Value *ResI  = Builder.CreateAdd(ResIl, ResIr, "mul.i");
416   return ComplexPairTy(ResR, ResI);
417 }
418 
419 ComplexPairTy ComplexExprEmitter::EmitBinDiv(const BinOpInfo &Op) {
420   llvm::Value *LHSr = Op.LHS.first, *LHSi = Op.LHS.second;
421   llvm::Value *RHSr = Op.RHS.first, *RHSi = Op.RHS.second;
422 
423   // (a+ib) / (c+id) = ((ac+bd)/(cc+dd)) + i((bc-ad)/(cc+dd))
424   llvm::Value *Tmp1 = Builder.CreateMul(LHSr, RHSr, "tmp"); // a*c
425   llvm::Value *Tmp2 = Builder.CreateMul(LHSi, RHSi, "tmp"); // b*d
426   llvm::Value *Tmp3 = Builder.CreateAdd(Tmp1, Tmp2, "tmp"); // ac+bd
427 
428   llvm::Value *Tmp4 = Builder.CreateMul(RHSr, RHSr, "tmp"); // c*c
429   llvm::Value *Tmp5 = Builder.CreateMul(RHSi, RHSi, "tmp"); // d*d
430   llvm::Value *Tmp6 = Builder.CreateAdd(Tmp4, Tmp5, "tmp"); // cc+dd
431 
432   llvm::Value *Tmp7 = Builder.CreateMul(LHSi, RHSr, "tmp"); // b*c
433   llvm::Value *Tmp8 = Builder.CreateMul(LHSr, RHSi, "tmp"); // a*d
434   llvm::Value *Tmp9 = Builder.CreateSub(Tmp7, Tmp8, "tmp"); // bc-ad
435 
436   llvm::Value *DSTr, *DSTi;
437   if (Tmp3->getType()->isFloatingPoint()) {
438     DSTr = Builder.CreateFDiv(Tmp3, Tmp6, "tmp");
439     DSTi = Builder.CreateFDiv(Tmp9, Tmp6, "tmp");
440   } else {
441     if (Op.Ty->getAsComplexType()->getElementType()->isUnsignedIntegerType()) {
442       DSTr = Builder.CreateUDiv(Tmp3, Tmp6, "tmp");
443       DSTi = Builder.CreateUDiv(Tmp9, Tmp6, "tmp");
444     } else {
445       DSTr = Builder.CreateSDiv(Tmp3, Tmp6, "tmp");
446       DSTi = Builder.CreateSDiv(Tmp9, Tmp6, "tmp");
447     }
448   }
449 
450   return ComplexPairTy(DSTr, DSTi);
451 }
452 
453 ComplexExprEmitter::BinOpInfo
454 ComplexExprEmitter::EmitBinOps(const BinaryOperator *E) {
455   TestAndClearIgnoreReal();
456   TestAndClearIgnoreImag();
457   TestAndClearIgnoreRealAssign();
458   TestAndClearIgnoreImagAssign();
459   BinOpInfo Ops;
460   Ops.LHS = Visit(E->getLHS());
461   Ops.RHS = Visit(E->getRHS());
462   Ops.Ty = E->getType();
463   return Ops;
464 }
465 
466 
467 // Compound assignments.
468 ComplexPairTy ComplexExprEmitter::
469 EmitCompoundAssign(const CompoundAssignOperator *E,
470                    ComplexPairTy (ComplexExprEmitter::*Func)(const BinOpInfo&)){
471   TestAndClearIgnoreReal();
472   TestAndClearIgnoreImag();
473   bool ignreal = TestAndClearIgnoreRealAssign();
474   bool ignimag = TestAndClearIgnoreImagAssign();
475   QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType();
476 
477   BinOpInfo OpInfo;
478 
479   // Load the RHS and LHS operands.
480   // __block variables need to have the rhs evaluated first, plus this should
481   // improve codegen a little.  It is possible for the RHS to be complex or
482   // scalar.
483   OpInfo.Ty = E->getComputationResultType();
484   OpInfo.RHS = EmitCast(E->getRHS(), OpInfo.Ty);
485 
486   LValue LHSLV = CGF.EmitLValue(E->getLHS());
487 
488 
489   // We know the LHS is a complex lvalue.
490   OpInfo.LHS=EmitLoadOfComplex(LHSLV.getAddress(),LHSLV.isVolatileQualified());
491   OpInfo.LHS=EmitComplexToComplexCast(OpInfo.LHS, LHSTy, OpInfo.Ty);
492 
493   // Expand the binary operator.
494   ComplexPairTy Result = (this->*Func)(OpInfo);
495 
496   // Truncate the result back to the LHS type.
497   Result = EmitComplexToComplexCast(Result, OpInfo.Ty, LHSTy);
498 
499   // Store the result value into the LHS lvalue.
500   EmitStoreOfComplex(Result, LHSLV.getAddress(), LHSLV.isVolatileQualified());
501   // And now return the LHS
502   IgnoreReal = ignreal;
503   IgnoreImag = ignimag;
504   IgnoreRealAssign = ignreal;
505   IgnoreImagAssign = ignimag;
506   return EmitLoadOfComplex(LHSLV.getAddress(), LHSLV.isVolatileQualified());
507 }
508 
509 ComplexPairTy ComplexExprEmitter::VisitBinAssign(const BinaryOperator *E) {
510   TestAndClearIgnoreReal();
511   TestAndClearIgnoreImag();
512   bool ignreal = TestAndClearIgnoreRealAssign();
513   bool ignimag = TestAndClearIgnoreImagAssign();
514   assert(CGF.getContext().getCanonicalType(E->getLHS()->getType()) ==
515          CGF.getContext().getCanonicalType(E->getRHS()->getType()) &&
516          "Invalid assignment");
517   // Emit the RHS.
518   ComplexPairTy Val = Visit(E->getRHS());
519 
520   // Compute the address to store into.
521   LValue LHS = CGF.EmitLValue(E->getLHS());
522 
523   // Store into it.
524   EmitStoreOfComplex(Val, LHS.getAddress(), LHS.isVolatileQualified());
525   // And now return the LHS
526   IgnoreReal = ignreal;
527   IgnoreImag = ignimag;
528   IgnoreRealAssign = ignreal;
529   IgnoreImagAssign = ignimag;
530   return EmitLoadOfComplex(LHS.getAddress(), LHS.isVolatileQualified());
531 }
532 
533 ComplexPairTy ComplexExprEmitter::VisitBinComma(const BinaryOperator *E) {
534   CGF.EmitStmt(E->getLHS());
535   CGF.EnsureInsertPoint();
536   return Visit(E->getRHS());
537 }
538 
539 ComplexPairTy ComplexExprEmitter::
540 VisitConditionalOperator(const ConditionalOperator *E) {
541   TestAndClearIgnoreReal();
542   TestAndClearIgnoreImag();
543   TestAndClearIgnoreRealAssign();
544   TestAndClearIgnoreImagAssign();
545   llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
546   llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
547   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
548 
549   llvm::Value *Cond = CGF.EvaluateExprAsBool(E->getCond());
550   Builder.CreateCondBr(Cond, LHSBlock, RHSBlock);
551 
552   CGF.EmitBlock(LHSBlock);
553 
554   // Handle the GNU extension for missing LHS.
555   assert(E->getLHS() && "Must have LHS for complex value");
556 
557   ComplexPairTy LHS = Visit(E->getLHS());
558   LHSBlock = Builder.GetInsertBlock();
559   CGF.EmitBranch(ContBlock);
560 
561   CGF.EmitBlock(RHSBlock);
562 
563   ComplexPairTy RHS = Visit(E->getRHS());
564   RHSBlock = Builder.GetInsertBlock();
565   CGF.EmitBranch(ContBlock);
566 
567   CGF.EmitBlock(ContBlock);
568 
569   // Create a PHI node for the real part.
570   llvm::PHINode *RealPN = Builder.CreatePHI(LHS.first->getType(), "cond.r");
571   RealPN->reserveOperandSpace(2);
572   RealPN->addIncoming(LHS.first, LHSBlock);
573   RealPN->addIncoming(RHS.first, RHSBlock);
574 
575   // Create a PHI node for the imaginary part.
576   llvm::PHINode *ImagPN = Builder.CreatePHI(LHS.first->getType(), "cond.i");
577   ImagPN->reserveOperandSpace(2);
578   ImagPN->addIncoming(LHS.second, LHSBlock);
579   ImagPN->addIncoming(RHS.second, RHSBlock);
580 
581   return ComplexPairTy(RealPN, ImagPN);
582 }
583 
584 ComplexPairTy ComplexExprEmitter::VisitChooseExpr(ChooseExpr *E) {
585   return Visit(E->getChosenSubExpr(CGF.getContext()));
586 }
587 
588 ComplexPairTy ComplexExprEmitter::VisitInitListExpr(InitListExpr *E) {
589     bool Ignore = TestAndClearIgnoreReal();
590     (void)Ignore;
591     assert (Ignore == false && "init list ignored");
592     Ignore = TestAndClearIgnoreImag();
593     (void)Ignore;
594     assert (Ignore == false && "init list ignored");
595   if (E->getNumInits())
596     return Visit(E->getInit(0));
597 
598   // Empty init list intializes to null
599   QualType Ty = E->getType()->getAsComplexType()->getElementType();
600   const llvm::Type* LTy = CGF.ConvertType(Ty);
601   llvm::Value* zeroConstant = llvm::Constant::getNullValue(LTy);
602   return ComplexPairTy(zeroConstant, zeroConstant);
603 }
604 
605 ComplexPairTy ComplexExprEmitter::VisitVAArgExpr(VAArgExpr *E) {
606   llvm::Value *ArgValue = CGF.EmitVAListRef(E->getSubExpr());
607   llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, E->getType());
608 
609   if (!ArgPtr) {
610     CGF.ErrorUnsupported(E, "complex va_arg expression");
611     const llvm::Type *EltTy =
612       CGF.ConvertType(E->getType()->getAsComplexType()->getElementType());
613     llvm::Value *U = llvm::UndefValue::get(EltTy);
614     return ComplexPairTy(U, U);
615   }
616 
617   // FIXME Volatility.
618   return EmitLoadOfComplex(ArgPtr, false);
619 }
620 
621 //===----------------------------------------------------------------------===//
622 //                         Entry Point into this File
623 //===----------------------------------------------------------------------===//
624 
625 /// EmitComplexExpr - Emit the computation of the specified expression of
626 /// complex type, ignoring the result.
627 ComplexPairTy CodeGenFunction::EmitComplexExpr(const Expr *E, bool IgnoreReal,
628                                                bool IgnoreImag, bool IgnoreRealAssign, bool IgnoreImagAssign) {
629   assert(E && E->getType()->isAnyComplexType() &&
630          "Invalid complex expression to emit");
631 
632   return ComplexExprEmitter(*this, IgnoreReal, IgnoreImag, IgnoreRealAssign,
633                             IgnoreImagAssign)
634     .Visit(const_cast<Expr*>(E));
635 }
636 
637 /// EmitComplexExprIntoAddr - Emit the computation of the specified expression
638 /// of complex type, storing into the specified Value*.
639 void CodeGenFunction::EmitComplexExprIntoAddr(const Expr *E,
640                                               llvm::Value *DestAddr,
641                                               bool DestIsVolatile) {
642   assert(E && E->getType()->isAnyComplexType() &&
643          "Invalid complex expression to emit");
644   ComplexExprEmitter Emitter(*this);
645   ComplexPairTy Val = Emitter.Visit(const_cast<Expr*>(E));
646   Emitter.EmitStoreOfComplex(Val, DestAddr, DestIsVolatile);
647 }
648 
649 /// StoreComplexToAddr - Store a complex number into the specified address.
650 void CodeGenFunction::StoreComplexToAddr(ComplexPairTy V,
651                                          llvm::Value *DestAddr,
652                                          bool DestIsVolatile) {
653   ComplexExprEmitter(*this).EmitStoreOfComplex(V, DestAddr, DestIsVolatile);
654 }
655 
656 /// LoadComplexFromAddr - Load a complex number from the specified address.
657 ComplexPairTy CodeGenFunction::LoadComplexFromAddr(llvm::Value *SrcAddr,
658                                                    bool SrcIsVolatile) {
659   return ComplexExprEmitter(*this).EmitLoadOfComplex(SrcAddr, SrcIsVolatile);
660 }
661