CGExprComplex.cpp revision c110c545810670871f54d0e999b5384ca0d6519d 
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"
22using namespace clang;
23using namespace CodeGen;
24
25//===----------------------------------------------------------------------===//
26//                        Complex Expression Emitter
27//===----------------------------------------------------------------------===//
28
29typedef CodeGenFunction::ComplexPairTy ComplexPairTy;
30
31namespace  {
32class VISIBILITY_HIDDEN ComplexExprEmitter
33  : public StmtVisitor<ComplexExprEmitter, ComplexPairTy> {
34  CodeGenFunction &CGF;
35  CGBuilderTy &Builder;
36public:
37  ComplexExprEmitter(CodeGenFunction &cgf) : CGF(cgf), Builder(CGF.Builder) {
38  }
39
40
41  //===--------------------------------------------------------------------===//
42  //                               Utilities
43  //===--------------------------------------------------------------------===//
44
45  /// EmitLoadOfLValue - Given an expression with complex type that represents a
46  /// value l-value, this method emits the address of the l-value, then loads
47  /// and returns the result.
48  ComplexPairTy EmitLoadOfLValue(const Expr *E) {
49    LValue LV = CGF.EmitLValue(E);
50    return EmitLoadOfComplex(LV.getAddress(), LV.isVolatileQualified());
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
97  // Operators.
98  ComplexPairTy VisitPrePostIncDec(const UnaryOperator *E,
99                                   bool isInc, bool isPre);
100  ComplexPairTy VisitUnaryPostDec(const UnaryOperator *E) {
101    return VisitPrePostIncDec(E, false, false);
102  }
103  ComplexPairTy VisitUnaryPostInc(const UnaryOperator *E) {
104    return VisitPrePostIncDec(E, true, false);
105  }
106  ComplexPairTy VisitUnaryPreDec(const UnaryOperator *E) {
107    return VisitPrePostIncDec(E, false, true);
108  }
109  ComplexPairTy VisitUnaryPreInc(const UnaryOperator *E) {
110    return VisitPrePostIncDec(E, true, true);
111  }
112  ComplexPairTy VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); }
113  ComplexPairTy VisitUnaryPlus     (const UnaryOperator *E) {
114    return Visit(E->getSubExpr());
115  }
116  ComplexPairTy VisitUnaryMinus    (const UnaryOperator *E);
117  ComplexPairTy VisitUnaryNot      (const UnaryOperator *E);
118  // LNot,Real,Imag never return complex.
119  ComplexPairTy VisitUnaryExtension(const UnaryOperator *E) {
120    return Visit(E->getSubExpr());
121  }
122  ComplexPairTy VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
123    return Visit(DAE->getExpr());
124  }
125  ComplexPairTy VisitCXXZeroInitValueExpr(CXXZeroInitValueExpr *E) {
126    assert(E->getType()->isAnyComplexType() && "Expected complex type!");
127    QualType Elem = E->getType()->getAsComplexType()->getElementType();
128    llvm::Constant *Null = llvm::Constant::getNullValue(CGF.ConvertType(Elem));
129    return ComplexPairTy(Null, Null);
130  }
131  ComplexPairTy VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
132    assert(E->getType()->isAnyComplexType() && "Expected complex type!");
133    QualType Elem = E->getType()->getAsComplexType()->getElementType();
134    llvm::Constant *Null = llvm::Constant::getNullValue(CGF.ConvertType(Elem));
135    return ComplexPairTy(Null, Null);
136  }
137
138  struct BinOpInfo {
139    ComplexPairTy LHS;
140    ComplexPairTy RHS;
141    QualType Ty;  // Computation Type.
142  };
143
144  BinOpInfo EmitBinOps(const BinaryOperator *E);
145  ComplexPairTy EmitCompoundAssign(const CompoundAssignOperator *E,
146                                   ComplexPairTy (ComplexExprEmitter::*Func)
147                                   (const BinOpInfo &));
148
149  ComplexPairTy EmitBinAdd(const BinOpInfo &Op);
150  ComplexPairTy EmitBinSub(const BinOpInfo &Op);
151  ComplexPairTy EmitBinMul(const BinOpInfo &Op);
152  ComplexPairTy EmitBinDiv(const BinOpInfo &Op);
153
154  ComplexPairTy VisitBinMul(const BinaryOperator *E) {
155    return EmitBinMul(EmitBinOps(E));
156  }
157  ComplexPairTy VisitBinAdd(const BinaryOperator *E) {
158    return EmitBinAdd(EmitBinOps(E));
159  }
160  ComplexPairTy VisitBinSub(const BinaryOperator *E) {
161    return EmitBinSub(EmitBinOps(E));
162  }
163  ComplexPairTy VisitBinDiv(const BinaryOperator *E) {
164    return EmitBinDiv(EmitBinOps(E));
165  }
166
167  // Compound assignments.
168  ComplexPairTy VisitBinAddAssign(const CompoundAssignOperator *E) {
169    return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinAdd);
170  }
171  ComplexPairTy VisitBinSubAssign(const CompoundAssignOperator *E) {
172    return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinSub);
173  }
174  ComplexPairTy VisitBinMulAssign(const CompoundAssignOperator *E) {
175    return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinMul);
176  }
177  ComplexPairTy VisitBinDivAssign(const CompoundAssignOperator *E) {
178    return EmitCompoundAssign(E, &ComplexExprEmitter::EmitBinDiv);
179  }
180
181  // GCC rejects rem/and/or/xor for integer complex.
182  // Logical and/or always return int, never complex.
183
184  // No comparisons produce a complex result.
185  ComplexPairTy VisitBinAssign     (const BinaryOperator *E);
186  ComplexPairTy VisitBinComma      (const BinaryOperator *E);
187
188
189  ComplexPairTy VisitConditionalOperator(const ConditionalOperator *CO);
190  ComplexPairTy VisitChooseExpr(ChooseExpr *CE);
191
192  ComplexPairTy VisitInitListExpr(InitListExpr *E);
193
194  ComplexPairTy VisitVAArgExpr(VAArgExpr *E);
195};
196}  // end anonymous namespace.
197
198//===----------------------------------------------------------------------===//
199//                                Utilities
200//===----------------------------------------------------------------------===//
201
202/// EmitLoadOfComplex - Given an RValue reference for a complex, emit code to
203/// load the real and imaginary pieces, returning them as Real/Imag.
204ComplexPairTy ComplexExprEmitter::EmitLoadOfComplex(llvm::Value *SrcPtr,
205                                                    bool isVolatile) {
206  llvm::SmallString<64> Name(SrcPtr->getNameStart(),
207                             SrcPtr->getNameStart()+SrcPtr->getNameLen());
208
209  Name += ".realp";
210  llvm::Value *RealPtr = Builder.CreateStructGEP(SrcPtr, 0, Name.c_str());
211
212  Name.pop_back();  // .realp -> .real
213  llvm::Value *Real = Builder.CreateLoad(RealPtr, isVolatile, Name.c_str());
214
215  Name.resize(Name.size()-4); // .real -> .imagp
216  Name += "imagp";
217
218  llvm::Value *ImagPtr = Builder.CreateStructGEP(SrcPtr, 1, Name.c_str());
219
220  Name.pop_back();  // .imagp -> .imag
221  llvm::Value *Imag = Builder.CreateLoad(ImagPtr, isVolatile, Name.c_str());
222  return ComplexPairTy(Real, Imag);
223}
224
225/// EmitStoreOfComplex - Store the specified real/imag parts into the
226/// specified value pointer.
227void ComplexExprEmitter::EmitStoreOfComplex(ComplexPairTy Val, llvm::Value *Ptr,
228                                            bool isVolatile) {
229  llvm::Value *RealPtr = Builder.CreateStructGEP(Ptr, 0, "real");
230  llvm::Value *ImagPtr = Builder.CreateStructGEP(Ptr, 1, "imag");
231
232  Builder.CreateStore(Val.first, RealPtr, isVolatile);
233  Builder.CreateStore(Val.second, ImagPtr, isVolatile);
234}
235
236
237
238//===----------------------------------------------------------------------===//
239//                            Visitor Methods
240//===----------------------------------------------------------------------===//
241
242ComplexPairTy ComplexExprEmitter::VisitExpr(Expr *E) {
243  CGF.ErrorUnsupported(E, "complex expression");
244  const llvm::Type *EltTy =
245    CGF.ConvertType(E->getType()->getAsComplexType()->getElementType());
246  llvm::Value *U = llvm::UndefValue::get(EltTy);
247  return ComplexPairTy(U, U);
248}
249
250ComplexPairTy ComplexExprEmitter::
251VisitImaginaryLiteral(const ImaginaryLiteral *IL) {
252  llvm::Value *Imag = CGF.EmitScalarExpr(IL->getSubExpr());
253  return ComplexPairTy(llvm::Constant::getNullValue(Imag->getType()), Imag);
254}
255
256
257ComplexPairTy ComplexExprEmitter::VisitCallExpr(const CallExpr *E) {
258  return CGF.EmitCallExpr(E).getComplexVal();
259}
260
261ComplexPairTy ComplexExprEmitter::VisitStmtExpr(const StmtExpr *E) {
262  return CGF.EmitCompoundStmt(*E->getSubStmt(), true).getComplexVal();
263}
264
265/// EmitComplexToComplexCast - Emit a cast from complex value Val to DestType.
266ComplexPairTy ComplexExprEmitter::EmitComplexToComplexCast(ComplexPairTy Val,
267                                                           QualType SrcType,
268                                                           QualType DestType) {
269  // Get the src/dest element type.
270  SrcType = SrcType->getAsComplexType()->getElementType();
271  DestType = DestType->getAsComplexType()->getElementType();
272
273  // C99 6.3.1.6: When a value of complex type is converted to another
274  // complex type, both the real and imaginary parts follow the conversion
275  // rules for the corresponding real types.
276  Val.first = CGF.EmitScalarConversion(Val.first, SrcType, DestType);
277  Val.second = CGF.EmitScalarConversion(Val.second, SrcType, DestType);
278  return Val;
279}
280
281ComplexPairTy ComplexExprEmitter::EmitCast(Expr *Op, QualType DestTy) {
282  // Two cases here: cast from (complex to complex) and (scalar to complex).
283  if (Op->getType()->isAnyComplexType())
284    return EmitComplexToComplexCast(Visit(Op), Op->getType(), DestTy);
285
286  // C99 6.3.1.7: When a value of real type is converted to a complex type, the
287  // real part of the complex result value is determined by the rules of
288  // conversion to the corresponding real type and the imaginary part of the
289  // complex result value is a positive zero or an unsigned zero.
290  llvm::Value *Elt = CGF.EmitScalarExpr(Op);
291
292  // Convert the input element to the element type of the complex.
293  DestTy = DestTy->getAsComplexType()->getElementType();
294  Elt = CGF.EmitScalarConversion(Elt, Op->getType(), DestTy);
295
296  // Return (realval, 0).
297  return ComplexPairTy(Elt, llvm::Constant::getNullValue(Elt->getType()));
298}
299
300ComplexPairTy ComplexExprEmitter::VisitPrePostIncDec(const UnaryOperator *E,
301                                                     bool isInc, bool isPre) {
302  LValue LV = CGF.EmitLValue(E->getSubExpr());
303  ComplexPairTy InVal = EmitLoadOfComplex(LV.getAddress(), LV.isVolatileQualified());
304
305  llvm::Value *NextVal;
306  if (isa<llvm::IntegerType>(InVal.first->getType())) {
307    uint64_t AmountVal = isInc ? 1 : -1;
308    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
309  } else {
310    QualType ElemTy = E->getType()->getAsComplexType()->getElementType();
311    llvm::APFloat FVal(CGF.getContext().getFloatTypeSemantics(ElemTy), 1);
312    if (!isInc)
313      FVal.changeSign();
314    NextVal = llvm::ConstantFP::get(FVal);
315  }
316
317  // Add the inc/dec to the real part.
318  NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
319
320  ComplexPairTy IncVal(NextVal, InVal.second);
321
322  // Store the updated result through the lvalue.
323  EmitStoreOfComplex(IncVal, LV.getAddress(), LV.isVolatileQualified());
324
325  // If this is a postinc, return the value read from memory, otherwise use the
326  // updated value.
327  return isPre ? IncVal : InVal;
328}
329
330ComplexPairTy ComplexExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
331  ComplexPairTy Op = Visit(E->getSubExpr());
332  llvm::Value *ResR = Builder.CreateNeg(Op.first,  "neg.r");
333  llvm::Value *ResI = Builder.CreateNeg(Op.second, "neg.i");
334  return ComplexPairTy(ResR, ResI);
335}
336
337ComplexPairTy ComplexExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
338  // ~(a+ib) = a + i*-b
339  ComplexPairTy Op = Visit(E->getSubExpr());
340  llvm::Value *ResI = Builder.CreateNeg(Op.second, "conj.i");
341  return ComplexPairTy(Op.first, ResI);
342}
343
344ComplexPairTy ComplexExprEmitter::EmitBinAdd(const BinOpInfo &Op) {
345  llvm::Value *ResR = Builder.CreateAdd(Op.LHS.first,  Op.RHS.first,  "add.r");
346  llvm::Value *ResI = Builder.CreateAdd(Op.LHS.second, Op.RHS.second, "add.i");
347  return ComplexPairTy(ResR, ResI);
348}
349
350ComplexPairTy ComplexExprEmitter::EmitBinSub(const BinOpInfo &Op) {
351  llvm::Value *ResR = Builder.CreateSub(Op.LHS.first,  Op.RHS.first,  "sub.r");
352  llvm::Value *ResI = Builder.CreateSub(Op.LHS.second, Op.RHS.second, "sub.i");
353  return ComplexPairTy(ResR, ResI);
354}
355
356
357ComplexPairTy ComplexExprEmitter::EmitBinMul(const BinOpInfo &Op) {
358  llvm::Value *ResRl = Builder.CreateMul(Op.LHS.first, Op.RHS.first, "mul.rl");
359  llvm::Value *ResRr = Builder.CreateMul(Op.LHS.second, Op.RHS.second,"mul.rr");
360  llvm::Value *ResR  = Builder.CreateSub(ResRl, ResRr, "mul.r");
361
362  llvm::Value *ResIl = Builder.CreateMul(Op.LHS.second, Op.RHS.first, "mul.il");
363  llvm::Value *ResIr = Builder.CreateMul(Op.LHS.first, Op.RHS.second, "mul.ir");
364  llvm::Value *ResI  = Builder.CreateAdd(ResIl, ResIr, "mul.i");
365  return ComplexPairTy(ResR, ResI);
366}
367
368ComplexPairTy ComplexExprEmitter::EmitBinDiv(const BinOpInfo &Op) {
369  llvm::Value *LHSr = Op.LHS.first, *LHSi = Op.LHS.second;
370  llvm::Value *RHSr = Op.RHS.first, *RHSi = Op.RHS.second;
371
372  // (a+ib) / (c+id) = ((ac+bd)/(cc+dd)) + i((bc-ad)/(cc+dd))
373  llvm::Value *Tmp1 = Builder.CreateMul(LHSr, RHSr, "tmp"); // a*c
374  llvm::Value *Tmp2 = Builder.CreateMul(LHSi, RHSi, "tmp"); // b*d
375  llvm::Value *Tmp3 = Builder.CreateAdd(Tmp1, Tmp2, "tmp"); // ac+bd
376
377  llvm::Value *Tmp4 = Builder.CreateMul(RHSr, RHSr, "tmp"); // c*c
378  llvm::Value *Tmp5 = Builder.CreateMul(RHSi, RHSi, "tmp"); // d*d
379  llvm::Value *Tmp6 = Builder.CreateAdd(Tmp4, Tmp5, "tmp"); // cc+dd
380
381  llvm::Value *Tmp7 = Builder.CreateMul(LHSi, RHSr, "tmp"); // b*c
382  llvm::Value *Tmp8 = Builder.CreateMul(LHSr, RHSi, "tmp"); // a*d
383  llvm::Value *Tmp9 = Builder.CreateSub(Tmp7, Tmp8, "tmp"); // bc-ad
384
385  llvm::Value *DSTr, *DSTi;
386  if (Tmp3->getType()->isFloatingPoint()) {
387    DSTr = Builder.CreateFDiv(Tmp3, Tmp6, "tmp");
388    DSTi = Builder.CreateFDiv(Tmp9, Tmp6, "tmp");
389  } else {
390    if (Op.Ty->getAsComplexType()->getElementType()->isUnsignedIntegerType()) {
391      DSTr = Builder.CreateUDiv(Tmp3, Tmp6, "tmp");
392      DSTi = Builder.CreateUDiv(Tmp9, Tmp6, "tmp");
393    } else {
394      DSTr = Builder.CreateSDiv(Tmp3, Tmp6, "tmp");
395      DSTi = Builder.CreateSDiv(Tmp9, Tmp6, "tmp");
396    }
397  }
398
399  return ComplexPairTy(DSTr, DSTi);
400}
401
402ComplexExprEmitter::BinOpInfo
403ComplexExprEmitter::EmitBinOps(const BinaryOperator *E) {
404  BinOpInfo Ops;
405  Ops.LHS = Visit(E->getLHS());
406  Ops.RHS = Visit(E->getRHS());
407  Ops.Ty = E->getType();
408  return Ops;
409}
410
411
412// Compound assignments.
413ComplexPairTy ComplexExprEmitter::
414EmitCompoundAssign(const CompoundAssignOperator *E,
415                   ComplexPairTy (ComplexExprEmitter::*Func)(const BinOpInfo&)){
416  QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType();
417
418  // Load the LHS and RHS operands.
419  LValue LHSLV = CGF.EmitLValue(E->getLHS());
420
421  BinOpInfo OpInfo;
422  OpInfo.Ty = E->getComputationType();
423
424  // We know the LHS is a complex lvalue.
425  OpInfo.LHS = EmitLoadOfComplex(LHSLV.getAddress(), LHSLV.isVolatileQualified());
426  OpInfo.LHS = EmitComplexToComplexCast(OpInfo.LHS, LHSTy, OpInfo.Ty);
427
428  // It is possible for the RHS to be complex or scalar.
429  OpInfo.RHS = EmitCast(E->getRHS(), OpInfo.Ty);
430
431  // Expand the binary operator.
432  ComplexPairTy Result = (this->*Func)(OpInfo);
433
434  // Truncate the result back to the LHS type.
435  Result = EmitComplexToComplexCast(Result, OpInfo.Ty, LHSTy);
436
437  // Store the result value into the LHS lvalue.
438  EmitStoreOfComplex(Result, LHSLV.getAddress(), LHSLV.isVolatileQualified());
439  return Result;
440}
441
442ComplexPairTy ComplexExprEmitter::VisitBinAssign(const BinaryOperator *E) {
443  assert(CGF.getContext().getCanonicalType(E->getLHS()->getType()) ==
444         CGF.getContext().getCanonicalType(E->getRHS()->getType()) &&
445         "Invalid assignment");
446  // Emit the RHS.
447  ComplexPairTy Val = Visit(E->getRHS());
448
449  // Compute the address to store into.
450  LValue LHS = CGF.EmitLValue(E->getLHS());
451
452  // Store into it.
453  EmitStoreOfComplex(Val, LHS.getAddress(), LHS.isVolatileQualified());
454  return Val;
455}
456
457ComplexPairTy ComplexExprEmitter::VisitBinComma(const BinaryOperator *E) {
458  CGF.EmitStmt(E->getLHS());
459  CGF.EnsureInsertPoint();
460  return Visit(E->getRHS());
461}
462
463ComplexPairTy ComplexExprEmitter::
464VisitConditionalOperator(const ConditionalOperator *E) {
465  llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
466  llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
467  llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
468
469  llvm::Value *Cond = CGF.EvaluateExprAsBool(E->getCond());
470  Builder.CreateCondBr(Cond, LHSBlock, RHSBlock);
471
472  CGF.EmitBlock(LHSBlock);
473
474  // Handle the GNU extension for missing LHS.
475  assert(E->getLHS() && "Must have LHS for complex value");
476
477  ComplexPairTy LHS = Visit(E->getLHS());
478  LHSBlock = Builder.GetInsertBlock();
479  CGF.EmitBranch(ContBlock);
480
481  CGF.EmitBlock(RHSBlock);
482
483  ComplexPairTy RHS = Visit(E->getRHS());
484  RHSBlock = Builder.GetInsertBlock();
485  CGF.EmitBranch(ContBlock);
486
487  CGF.EmitBlock(ContBlock);
488
489  // Create a PHI node for the real part.
490  llvm::PHINode *RealPN = Builder.CreatePHI(LHS.first->getType(), "cond.r");
491  RealPN->reserveOperandSpace(2);
492  RealPN->addIncoming(LHS.first, LHSBlock);
493  RealPN->addIncoming(RHS.first, RHSBlock);
494
495  // Create a PHI node for the imaginary part.
496  llvm::PHINode *ImagPN = Builder.CreatePHI(LHS.first->getType(), "cond.i");
497  ImagPN->reserveOperandSpace(2);
498  ImagPN->addIncoming(LHS.second, LHSBlock);
499  ImagPN->addIncoming(RHS.second, RHSBlock);
500
501  return ComplexPairTy(RealPN, ImagPN);
502}
503
504ComplexPairTy ComplexExprEmitter::VisitChooseExpr(ChooseExpr *E) {
505  return Visit(E->getChosenSubExpr(CGF.getContext()));
506}
507
508ComplexPairTy ComplexExprEmitter::VisitInitListExpr(InitListExpr *E) {
509  if (E->getNumInits())
510    return Visit(E->getInit(0));
511
512  // Empty init list intializes to null
513  QualType Ty = E->getType()->getAsComplexType()->getElementType();
514  const llvm::Type* LTy = CGF.ConvertType(Ty);
515  llvm::Value* zeroConstant = llvm::Constant::getNullValue(LTy);
516  return ComplexPairTy(zeroConstant, zeroConstant);
517}
518
519ComplexPairTy ComplexExprEmitter::VisitVAArgExpr(VAArgExpr *E) {
520  llvm::Value *ArgValue = CGF.EmitVAListRef(E->getSubExpr());
521  llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, E->getType());
522
523  if (!ArgPtr) {
524    CGF.ErrorUnsupported(E, "complex va_arg expression");
525    const llvm::Type *EltTy =
526      CGF.ConvertType(E->getType()->getAsComplexType()->getElementType());
527    llvm::Value *U = llvm::UndefValue::get(EltTy);
528    return ComplexPairTy(U, U);
529  }
530
531  // FIXME Volatility.
532  return EmitLoadOfComplex(ArgPtr, false);
533}
534
535//===----------------------------------------------------------------------===//
536//                         Entry Point into this File
537//===----------------------------------------------------------------------===//
538
539/// EmitComplexExpr - Emit the computation of the specified expression of
540/// complex type, ignoring the result.
541ComplexPairTy CodeGenFunction::EmitComplexExpr(const Expr *E) {
542  assert(E && E->getType()->isAnyComplexType() &&
543         "Invalid complex expression to emit");
544
545  return ComplexExprEmitter(*this).Visit(const_cast<Expr*>(E));
546}
547
548/// EmitComplexExprIntoAddr - Emit the computation of the specified expression
549/// of complex type, storing into the specified Value*.
550void CodeGenFunction::EmitComplexExprIntoAddr(const Expr *E,
551                                              llvm::Value *DestAddr,
552                                              bool DestIsVolatile) {
553  assert(E && E->getType()->isAnyComplexType() &&
554         "Invalid complex expression to emit");
555  ComplexExprEmitter Emitter(*this);
556  ComplexPairTy Val = Emitter.Visit(const_cast<Expr*>(E));
557  Emitter.EmitStoreOfComplex(Val, DestAddr, DestIsVolatile);
558}
559
560/// StoreComplexToAddr - Store a complex number into the specified address.
561void CodeGenFunction::StoreComplexToAddr(ComplexPairTy V,
562                                         llvm::Value *DestAddr,
563                                         bool DestIsVolatile) {
564  ComplexExprEmitter(*this).EmitStoreOfComplex(V, DestAddr, DestIsVolatile);
565}
566
567/// LoadComplexFromAddr - Load a complex number from the specified address.
568ComplexPairTy CodeGenFunction::LoadComplexFromAddr(llvm::Value *SrcAddr,
569                                                   bool SrcIsVolatile) {
570  return ComplexExprEmitter(*this).EmitLoadOfComplex(SrcAddr, SrcIsVolatile);
571}
572