Change a bit the implementation of GAS instruction

[Delivers #79942174]

evmcc/Compiler.cpp

@@ -690,8 +690,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 
 			case Instruction::GAS:
 			{
-				auto value = builder.CreateLoad(gasMeter.getLLVMGasVar());
+				stack.push(gasMeter.getGas());
-				stack.push(value);
 				break;
 			}
 

evmcc/GasMeter.cpp

@@ -167,9 +167,9 @@ void GasMeter::checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilde
 	_builder.CreateCall(m_gasCheckFunc, cost);
 }
 
-llvm::GlobalVariable* GasMeter::getLLVMGasVar()
+llvm::Value* GasMeter::getGas()
 {
-	return m_gas;
+	m_builder.CreateLoad(m_gas, "gas");
 }
 
 }

evmcc/GasMeter.h

@@ -32,7 +32,7 @@ public:
 	/// Generate code that checks the cost of additional memory used by program
 	void checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder);
 
-	llvm::GlobalVariable* getLLVMGasVar();
+	llvm::Value* getGas();
 
 private:
 	/// Cumulative gas cost of a block of instructions