Split complex arithmetic codegen out from aggregate codegen.
This means that we get rid of tons of intermediate allocas.  For
example:

void foo(double _Complex a, double _Complex b) {
   a = b+a+a;
}

this used to have 4 temporary allocas, now it has zero of them.
This also simplifies the individual visitor methods because they
now can all operate on real/imag pairs instead of having to 
load/store all over the place.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@41217 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CGComplexExpr.cpp b/CodeGen/CGComplexExpr.cpp
new file mode 100644
index 0000000..719e22a
--- /dev/null
+++ b/CodeGen/CGComplexExpr.cpp
@@ -0,0 +1,313 @@
+//===--- CGComplexExpr.cpp - Emit LLVM Code for Complex Exprs -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit Expr nodes with complex types as LLVM code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "CodeGenModule.h"
+#include "clang/AST/AST.h"
+#include "llvm/Constants.h"
+#include "llvm/Function.h"
+#include "llvm/Support/Compiler.h"
+using namespace clang;
+using namespace CodeGen;
+
+//===----------------------------------------------------------------------===//
+//                        Aggregate Expression Emitter
+//===----------------------------------------------------------------------===//
+
+typedef std::pair<llvm::Value *, llvm::Value *> ComplexPairTy;
+
+namespace  {
+class VISIBILITY_HIDDEN ComplexExprEmitter
+  : public StmtVisitor<ComplexExprEmitter, ComplexPairTy> {
+  CodeGenFunction &CGF;
+public:
+  ComplexExprEmitter(CodeGenFunction &cgf) : CGF(cgf) {
+  }
+
+  
+  //===--------------------------------------------------------------------===//
+  //                               Utilities
+  //===--------------------------------------------------------------------===//
+
+  /// EmitLoadOfLValue - Given an expression with complex type that represents a
+  /// value l-value, this method emits the address of the l-value, then loads
+  /// and returns the result.
+  ComplexPairTy EmitLoadOfLValue(const Expr *E);
+  
+  
+  //===--------------------------------------------------------------------===//
+  //                            Visitor Methods
+  //===--------------------------------------------------------------------===//
+  
+  ComplexPairTy VisitStmt(Stmt *S) {
+    fprintf(stderr, "Unimplemented agg expr!\n");
+    S->dump();
+    return ComplexPairTy();
+  }
+  ComplexPairTy VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr());}
+
+  // l-values.
+  ComplexPairTy VisitDeclRefExpr(DeclRefExpr *DRE) {
+    return EmitLoadOfLValue(DRE);
+  }
+  //  case Expr::ArraySubscriptExprClass:
+
+  // Operators.
+  //  case Expr::UnaryOperatorClass:
+  //  case Expr::ImplicitCastExprClass:
+  //  case Expr::CastExprClass: 
+  //  case Expr::CallExprClass:
+  ComplexPairTy VisitBinaryOperator(const BinaryOperator *BO);
+  ComplexPairTy VisitBinAdd        (const BinaryOperator *E);
+  ComplexPairTy VisitBinAssign     (const BinaryOperator *E);
+
+  
+  ComplexPairTy VisitConditionalOperator(const ConditionalOperator *CO);
+  //  case Expr::ChooseExprClass:
+};
+}  // end anonymous namespace.
+
+//===----------------------------------------------------------------------===//
+//                                Utilities
+//===----------------------------------------------------------------------===//
+
+/// EmitLoadOfLValue - Given an expression with complex type that represents a
+/// value l-value, this method emits the address of the l-value, then loads
+/// and returns the result.
+ComplexPairTy ComplexExprEmitter::EmitLoadOfLValue(const Expr *E) {
+  LValue LV = CGF.EmitLValue(E);
+  assert(LV.isSimple() && "Can't have complex bitfield, vector, etc");
+  
+  // Load the real/imag values.
+  llvm::Value *Real, *Imag;
+  CGF.EmitLoadOfComplex(LV.getAddress(), Real, Imag);
+  return ComplexPairTy(Real, Imag);
+}
+
+//===----------------------------------------------------------------------===//
+//                            Visitor Methods
+//===----------------------------------------------------------------------===//
+
+ComplexPairTy ComplexExprEmitter::VisitBinaryOperator(const BinaryOperator *E) {
+  fprintf(stderr, "Unimplemented aggregate binary expr!\n");
+  E->dump();
+  return ComplexPairTy();
+#if 0
+  switch (E->getOpcode()) {
+  default:
+    return;
+  case BinaryOperator::Mul:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitMul(LHS, RHS, E->getType());
+  case BinaryOperator::Div:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitDiv(LHS, RHS, E->getType());
+  case BinaryOperator::Rem:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitRem(LHS, RHS, E->getType());
+  case BinaryOperator::Add:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    if (!E->getType()->isPointerType())
+      return EmitAdd(LHS, RHS, E->getType());
+      
+      return EmitPointerAdd(LHS, E->getLHS()->getType(),
+                            RHS, E->getRHS()->getType(), E->getType());
+  case BinaryOperator::Sub:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    
+    if (!E->getLHS()->getType()->isPointerType())
+      return EmitSub(LHS, RHS, E->getType());
+      
+      return EmitPointerSub(LHS, E->getLHS()->getType(),
+                            RHS, E->getRHS()->getType(), E->getType());
+  case BinaryOperator::Shl:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitShl(LHS, RHS, E->getType());
+  case BinaryOperator::Shr:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitShr(LHS, RHS, E->getType());
+  case BinaryOperator::And:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitAnd(LHS, RHS, E->getType());
+  case BinaryOperator::Xor:
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitXor(LHS, RHS, E->getType());
+  case BinaryOperator::Or :
+    LHS = EmitExpr(E->getLHS());
+    RHS = EmitExpr(E->getRHS());
+    return EmitOr(LHS, RHS, E->getType());
+  case BinaryOperator::MulAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitMul(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::DivAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitDiv(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::RemAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitRem(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::AddAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitAdd(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::SubAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitSub(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::ShlAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitShl(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::ShrAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitShr(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::AndAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitAnd(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::OrAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitOr(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::XorAssign: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(E);
+    LValue LHSLV;
+    EmitCompoundAssignmentOperands(CAO, LHSLV, LHS, RHS);
+    LHS = EmitXor(LHS, RHS, CAO->getComputationType());
+    return EmitCompoundAssignmentResult(CAO, LHSLV, LHS);
+  }
+  case BinaryOperator::Comma: return EmitBinaryComma(E);
+  }
+#endif
+}
+
+ComplexPairTy ComplexExprEmitter::VisitBinAdd(const BinaryOperator *E) {
+  // This must be a complex number.
+  ComplexPairTy LHS = Visit(E->getLHS());
+  ComplexPairTy RHS = Visit(E->getRHS());
+  
+  llvm::Value *ResR = CGF.Builder.CreateAdd(LHS.first,  RHS.first,  "add.r");
+  llvm::Value *ResI = CGF.Builder.CreateAdd(LHS.second, RHS.second, "add.i");
+
+  return ComplexPairTy(ResR, ResI);
+}
+
+ComplexPairTy ComplexExprEmitter::VisitBinAssign(const BinaryOperator *E) {
+  assert(E->getLHS()->getType().getCanonicalType() ==
+         E->getRHS()->getType().getCanonicalType() && "Invalid assignment");
+  // Emit the RHS.
+  ComplexPairTy Val = Visit(E->getRHS());
+
+  // Compute the address to store into.
+  LValue LHS = CGF.EmitLValue(E->getLHS());
+  
+  // Store into it.
+  // FIXME: Volatility!
+  CGF.EmitStoreOfComplex(Val.first, Val.second, LHS.getAddress());
+  return Val;
+}
+
+
+ComplexPairTy ComplexExprEmitter::
+VisitConditionalOperator(const ConditionalOperator *E) {
+  llvm::BasicBlock *LHSBlock = new llvm::BasicBlock("cond.?");
+  llvm::BasicBlock *RHSBlock = new llvm::BasicBlock("cond.:");
+  llvm::BasicBlock *ContBlock = new llvm::BasicBlock("cond.cont");
+  
+  llvm::Value *Cond = CGF.EvaluateExprAsBool(E->getCond());
+  CGF.Builder.CreateCondBr(Cond, LHSBlock, RHSBlock);
+  
+  CGF.EmitBlock(LHSBlock);
+  
+  // Handle the GNU extension for missing LHS.
+  assert(E->getLHS() && "Must have LHS for aggregate value");
+
+  ComplexPairTy LHS = Visit(E->getLHS());
+  CGF.Builder.CreateBr(ContBlock);
+  LHSBlock = CGF.Builder.GetInsertBlock();
+  
+  CGF.EmitBlock(RHSBlock);
+  
+  ComplexPairTy RHS = Visit(E->getRHS());
+  CGF.Builder.CreateBr(ContBlock);
+  RHSBlock = CGF.Builder.GetInsertBlock();
+  
+  CGF.EmitBlock(ContBlock);
+  
+  // Create a PHI node for the real part.
+  llvm::PHINode *RealPN = CGF.Builder.CreatePHI(LHS.first->getType(), "cond.r");
+  RealPN->reserveOperandSpace(2);
+  RealPN->addIncoming(LHS.first, LHSBlock);
+  RealPN->addIncoming(RHS.first, RHSBlock);
+
+  // Create a PHI node for the imaginary part.
+  llvm::PHINode *ImagPN = CGF.Builder.CreatePHI(LHS.first->getType(), "cond.i");
+  ImagPN->reserveOperandSpace(2);
+  ImagPN->addIncoming(LHS.second, LHSBlock);
+  ImagPN->addIncoming(RHS.second, RHSBlock);
+  
+  return ComplexPairTy(RealPN, ImagPN);
+}
+
+//===----------------------------------------------------------------------===//
+//                         Entry Point into this File
+//===----------------------------------------------------------------------===//
+
+/// EmitComplexExpr - Emit the computation of the specified expression of
+/// complex type, ignoring the result.
+void CodeGenFunction::EmitComplexExpr(const Expr *E) {
+  assert(E && E->getType()->isComplexType() &&
+         "Invalid complex expression to emit");
+  
+  ComplexExprEmitter(*this).Visit(const_cast<Expr*>(E));
+}
+