C++ (Cpp) CodeGenFunction::ConstantFoldsToSimpleInteger Examples

Example #1

File: CGStmtOpenMP.cpp Project: 4ntoine/clang

/// \brief Emits code for OpenMP 'if' clause using specified \a CodeGen
/// function. Here is the logic:
/// if (Cond) {
///   CodeGen(true);
/// } else {
///   CodeGen(false);
/// }
static void EmitOMPIfClause(CodeGenFunction &CGF, const Expr *Cond,
                            const std::function<void(bool)> &CodeGen) {
  CodeGenFunction::LexicalScope ConditionScope(CGF, Cond->getSourceRange());

  // If the condition constant folds and can be elided, try to avoid emitting
  // the condition and the dead arm of the if/else.
  bool CondConstant;
  if (CGF.ConstantFoldsToSimpleInteger(Cond, CondConstant)) {
    CodeGen(CondConstant);
    return;
  }

  // Otherwise, the condition did not fold, or we couldn't elide it.  Just
  // emit the conditional branch.
  auto ThenBlock = CGF.createBasicBlock(/*name*/ "omp_if.then");
  auto ElseBlock = CGF.createBasicBlock(/*name*/ "omp_if.else");
  auto ContBlock = CGF.createBasicBlock(/*name*/ "omp_if.end");
  CGF.EmitBranchOnBoolExpr(Cond, ThenBlock, ElseBlock, /*TrueCount*/ 0);

  // Emit the 'then' code.
  CGF.EmitBlock(ThenBlock);
  CodeGen(/*ThenBlock*/ true);
  CGF.EmitBranch(ContBlock);
  // Emit the 'else' code if present.
  {
    // There is no need to emit line number for unconditional branch.
    SuppressDebugLocation SDL(CGF.Builder);
    CGF.EmitBlock(ElseBlock);
  }
  CodeGen(/*ThenBlock*/ false);
  {
    // There is no need to emit line number for unconditional branch.
    SuppressDebugLocation SDL(CGF.Builder);
    CGF.EmitBranch(ContBlock);
  }
  // Emit the continuation block for code after the if.
  CGF.EmitBlock(ContBlock, /*IsFinished*/ true);
}