Memory access instruction reordering

A method, comprising:

• performing data processing;
• and
• decoding instructions to control performing the data processing;
• imposing an ordering requirement on one or more memory access instructions to prevent said one or more memory access instructions being reordered with respect to an ordering instruction;
• and
• in response to an ordering limit hint instruction associated with a given ordering instruction, relaxing the ordering requirement for a memory access instruction for which the ordering limit hint instruction appears in program order between the memory access instruction and the given ordering instruction.

A non-transitory computer-readable medium storing a computer program comprising instructions which, when executed by a host data processing apparatus, control the host data processing apparatus to provide an instruction execution environment for execution of target program code, the computer program comprising:

• processing program logic configured to perform data processing;
• and
• instruction decoding program logic configured to decode instructions of the target program code to control the processing program logic to perform the data processing;
• in which:
• the processing program logic is configured to impose an ordering requirement on one or more memory access instructions to prevent said one or more memory access instructions being reordered with respect to an ordering instruction;
• and
• in response to an ordering limit hint instruction associated with a given ordering instruction, the instruction decoding program logic is configured to control the processing program logic to relax the ordering requirement for a memory access instruction for which the ordering limit hint instruction appears in program order between the memory access instruction and the given ordering instruction.