Function CodegenGcd

be/src/codegen/instruction-counter-test.cc:114–150

IR output from CodegenGcd define i32 @gcd(i32 %x, i32 %y) { entry: %tmp = icmp eq i32 %x, %y br i1 %tmp, label %return, label %cond_false return: ; preds = %entry ret i32 %x cond_false: ; preds = %entry %tmp2 = icmp ult i32 %x, %y br i1 %tmp2, label %cond_true, label %cond_false1 cond_true:

// LLVM IR module which contains one function to return the GCD of two numbers
// }
llvm::Module* CodegenGcd(llvm::LLVMContext* context) {
  llvm::Module* mod = new llvm::Module("gcd", *context);
  llvm::Constant* c = mod->getOrInsertFunction("gcd",
      llvm::IntegerType::get(*context, 32), llvm::IntegerType::get(*context, 32),
      llvm::IntegerType::get(*context, 32));
  llvm::Function* gcd = llvm::cast<llvm::Function>(c);
  llvm::Function::arg_iterator args = gcd->arg_begin();
  llvm::Value* x = &*args;
  ++args;
  x->setName("x");
  llvm::Value* y = &*args;
  ++args;
  y->setName("y");
  llvm::BasicBlock* entry = llvm::BasicBlock::Create(*context, "entry", gcd);
  llvm::BasicBlock* ret = llvm::BasicBlock::Create(*context, "return", gcd);
  llvm::BasicBlock* cond_false = llvm::BasicBlock::Create(*context, "cond_false", gcd);
  llvm::BasicBlock* cond_true = llvm::BasicBlock::Create(*context, "cond_true", gcd);
  llvm::BasicBlock* cond_false_2 = llvm::BasicBlock::Create(*context, "cond_false", gcd);
  llvm::IRBuilder<> builder(entry);
  llvm::Value* xEqualsY = builder.CreateICmpEQ(x, y, "tmp");
  builder.CreateCondBr(xEqualsY, ret, cond_false);  builder.SetInsertPoint(ret);
  builder.CreateRet(x);
  builder.SetInsertPoint(cond_false);
  llvm::Value* xLessThanY = builder.CreateICmpULT(x, y, "tmp");
  builder.CreateCondBr(xLessThanY, cond_true, cond_false_2);
  builder.SetInsertPoint(cond_true);
  llvm::Value* yMinusX = builder.CreateSub(y, x, "tmp");
  llvm::Value* args1[2] = {x, yMinusX};
  llvm::Value* recur_1 = builder.CreateCall(gcd, args1, "tmp");
  builder.CreateRet(recur_1);
  builder.SetInsertPoint(cond_false_2);
  llvm::Value* xMinusY = builder.CreateSub(x, y, "tmp");
  llvm::Value* args2[2] = {xMinusY, y};
  llvm::Value* recur_2 = builder.CreateCall(gcd, args2, "tmp");
  builder.CreateRet(recur_2);
  return mod;
}

TEST_F(InstructionCounterTest, TestMemInstrCount) {
  llvm::Module* GcdModule = CodegenGcd(&context_);